Welcome to the forums!
I don't know what your "very tight budget" actually allows, but you may even be able to consider a K-70 if you can find one for a very good deal. I bought one (body only) from Amazon Warehouse not long ago for under $350. It is a very powerful camera for the money (even closer to full price). Full disclosure, though: I have since had reliability issues with it (I believe my own fault, but it makes me slightly hesitant to give a strong recommendation).
A secondhand higher end camera, like a K-5 or K-3, should be a good choice (again, not knowing exactly what your budget is). If you haven't already, check out
the user review database of K-mount DSLRs. They are listed with the newest at the top and the oldest at the bottom, and should therefore generally be in descending price order as well. Don't pay too much attention to the prices listed on that page, though. Ebay (for used peer to peer prices) and KEH (for used camera shop prices) are probably a better guide for what to expect to pay for a used older camera. And since you're in Indiana, it might make sense to check out Robert's/
UsedPhotoPro.