We're on our third fire pit now. The first one was just a basic bowl. It didn't have any drain holes and would fill up with water. I drilled holes to help with drainage, but it eventually rusted out anyway.
The second one was better quality, but sitting out in the weather on the patio it rusted through in a few years also.
The third one is the exact same model as the second, but I started pulling it out of the weather in the fall. I haven't had it long enough to know whether it will make any difference in the longevity. I just assume I'll need a new fire pit every 2-3 years.
Like PB4USKI, we have a woodstove in our house so we always have a supply of firewood. I also enjoy woodworking, so there's a never ending supply of cutoffs from that hobby. Most stores in our area (especially smaller general stores or hardware stores) carry small bundles of real firewood. It's expensive if you burn a lot, but just for an occasional fire it might be OK.
I started using "Fatwood" years ago to light fires in our woodstove and it works great in the firepit too. Just grab a couple sticks of Fatwood, light it with a match, add small kindling and work my way up to larger sticks and logs. I can have a four foot flame in about 10 minutes.
I always extinguish our fire with the garden hose at the end of the night. I start with a light spray and haven't noticed any metal warping on any of our firepits. I'm sure the moisture helps accelerate the rust, but I would rather destroy the firepit than accidentally start a forest fire.
Check your local burning status before building a fire. Around here we have an automatic four month burn ban every summer. Firepits are usually still allowed unless conditions are really dry. I usually won't burn if it's too dry, even if legally I can. I always check the requirements online before burning.