Ebay or even craigslist is a great source for that kind of gear, because it's cheap but was built to last forever (and does). For example I got an OG Presto pressure cooker for $5 and a replacement gasket off ebay for another $5. You'd get the same thing much more cheaply made for $30 new.
I absolutely agree I absolutely agree with the advice about boiling water. And then I use a scrub brush and more hot water over the sink to get the debris out. After that I put a little flax oil on the pan just a very very thin layer, heat it a bit and wipe it off with a paper towel. Good to go...