Having a difficult time coming up with an idea for my MIL for Christmas. She has multiple dietary restrictions, so any food related gifts are out, including restaurant gift certificates. She doesn’t get dressed up, so clothes are out. Even if I got her new sweats, the size or color would be wrong and she would just end up returning them, based on past practice. She has stated that she doesn’t plan to decorate this year, as too much work, so I thought of a wreath for her door. It comes with a hanger, so all she has to do is take it out of the box and hang it up. Then at least she will have something Christmas-y without the work of getting the decorations out of storage. DH nixed that idea. I found a pin in a design that she likes, that would have the birthstones of the kids and grandkids, but DH thought it was too small. We decided to use that concept for something nicer for her upcoming birthday. I have told DH to handle this, since he didn’t like either of my suggestions, but I know he’s going to wait until the last minute and I just want to be done shopping. Looking to keep it under $50.
I bought mine some team-logo sock slippers and crew socks (Iowa Hawkeyes and Chicago Bears, respectively; repulsive!).
She spends a lot of time walking around barefoot on her chilly wood floors. These would help.
Both cost about $25 combined on eBay. My wife is thrilled.
I would no doubt give her the $50 in $1 bills. Just a thought.
It is often surprising how people who do not actually need the money still like to receive it.
Otherwise, a gift card for Target or her local grocery store or Macy’s or whatever.
For me it would be Amazon!
I know you said no food gifts, but I’m getting mom Omaha steaks again this Christmas. That way her fridge is stocked for the winter, and she won’t have to go out in the cold and wet weather.
How about a supermarket gift card? Possibly set up a Peapod type of account so she can have groceries delivered?
Could you do something with a photo of the grandkids?
How about tickets to some sort of an event? For mom’s birthday (in October) I got her tickets – we’re seeing Handel’s Messiah at a local college in 2 weeks.
A movie gift card?
You can find tabletop Christmas trees-- one year we had one delivered to my inlaws when dad was ill and decorating was too difficult.
Nice pair of slippers?
How about a GC for a cleaning service (a small house or apt would probably fall under $50). Or maybe tickets to a local theater production. Local venues can sometimes be very reasonably priced. GC to the place she gets her hair done?
You don’t have a problem with ideas for your mil, you have a problem with your H. ;). I can relate, mine is the same. Nixes all the ideas, has none of his own and expects me to come up with others.
It annoys the c r a p out of me. This year I bought stuff for his parents and didn’t tell him. He won’t remember to ask if I don’t tell him. Works for us. And I was boring, a shirt and vest from talbots for mil. A wool and cashmere sweater for fil from Nordstrom. They can return them, I am beyond caring anymore.
My mom struggles since my dad passed away. She’s getting money that she will use to buy mulch or something for her yard. And a rosary that I bought in Rome.
MIL has her house on the market and the realtor insisted she take the carpet out of the master bath and replace it with tile, which in our market is very sound advice. MIL is 82, and though in very good health and mentally sharp as ever, is quite worried about falling on that tile. I think the skid resistant sock idea is great. I will get some of those today, though they won’t be sports themed, lol. She couldn’t possibly care less about sports.
We have a similar problem, but decided to stop thinking so hard about it and just bought my MIL an amaryllis. She loved it. But if DH is supposed to do the gifting, why intervene? Let him figure it out, and you can cheerfully point fingers later 
p.s. MILs favorite gift is her birthday, when I send DH to visit his parents for an entire weekend, just them. He takes her shopping, fixes things, cleans, etc. They look forward to it, and so do FIL and I!
Books? A magazine subscription?
Something like this:
I just bought mine a digital picture frame that is cloud enabled. You can manage it remotely if she is technologically challenged. If you have the dedicated email, anyone can push photos from phone or computer and they automatically appear like magic. Your MIL will need wireless in her home, however, for this to work. Got it on Amazon, there are various options and price points. I figured this way she could get a steady supply of grandchild photos.
Does she have a cell phone or iPAD? Get a Jackery (portable battery source). Everybody loves them.
I bought a little table top Christmas tree for my parents years ago when they quit decorating. They really enjoyed it.
My mom and aunt always liked the Reader’s Digest subscription–my dad said it was like getting a gift every month.
Sounds like your husband should be picking out the gift for is own mom. 
Does she enjoy reading? Books, gift card to book store, magazine subscriptions?
Does she get her hair or nails done? A gift certificate to a nail or hair salon would be nice. This is what we usually get my MIL as she does not want household items or clothing. I usually make up a little food basket of gourmet items and also get a gas card. It has become boring and predictable but husband also nixes any new ideas, so that’s what it will be again this year.
Is she in a cold part of the country? How about a set of fleece bedsheets?
My 81 year old mom asked for a Bernie Sanders t-shirt! (I don’t recommend that for everyone!)
My 91 year old MIL (who just retired from working at Walmart ) drinks a glass of Port every night with dinner. So, we always give her a case of her favorite. For Mother’s Day/Birthday (they are very close together) we give her some of her favorite perfume. She uses it up in a year, so it is perfect.
I just got my MIL a needlepoint pattern from Amazon that was about $50. I know she likes needlepoint, and this one was a really cool butterfly pattern.
You could also do a flowers of the month club, where they deliver cut flowers every month. Good for people who have too much “stuff” and it’s something to look forward to every month. It’s probably more than your $50 limit, though.
Would your husband approve of a Christmas centerpiece? LL Bean has a pretty one with a LED candle… I buy wreaths and centerpieces for my older relatives that don’t decorate any more and they seem to enjoy them.