<p>Purdue is public (state of Indiana).</p>
<p>Try using the net price calculators at each school to get an estimate of financial aid and net price that you are likely to get at each school.</p>
<p>Double majoring may be difficult, and generally not considered by employers except for very specific circumstances. On the other hand, it does appear that a minor in architecture is not that uncommon for civil engineering students.</p>