Definitely skip the hardware store soldering irons, but that doesn't mean you have to spend a ton. I got a knockoff Hakko 936 for like $20 and I have no complaints.
As much as I love metcals, we had a $100 Aoyue hot-air station in graduate school that probably soldered on 500+ custom ASICs over its lifespan. The thing with prototyping chips (as with anything else) is you don't want to insert a variable (bad solder joints) into something that might have other unknown variables (the chip). The $100 hot air station broke somewhere around chip #400 and we just kept cobbling it back together. I think its still working to this day.
