I have the aforementioned Elegoo Mars, for about 9 months now. It's cheap and cheerful and produces decent quality prints. Not the best quality, but its a very cheap machine to buy into 3d printing; your getting 80 percent of the quality of a good printer for a lot less than 80 percent of the price. Resin printing itself is a bit of an art- be prepared for quite a bit of failure and tweaking. It's messy too, and resin has to be handled carefully.
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Most of what I print I have designed myself, so I don't often go looking for files. There's a lot of free stuff out there - just google "*name* stl" and you'll find something. But its very eclectic and pretty random. Better stuff can be found through Kickstarters and Patreon.
As a designer, the pervading expectation of everything being free that many in the printing community seem to hold, is kinda irksome. For a consumer of products it's great though. There's room for both, but so much free stuff decreases the willingness to pay for anything. Kinda like what happened with music. But that's getting off the point.
Depends what you want- lots of good scenery for free, but for nice miniatures, you'll have to pay a little.