You would also need a computer with your 3d printer as you just don’t feed printer with files from internet. (Actually, they are a few case where you can but it is very limited). As for your question: To save money, you need to earn money…

Can’t talk for the price but you won’t find an other company that match as much your requirements, only issue with prusa mini is the small print area but depending what you want to do, it can be enough.

Do you have on of those plastic extruder? If so, check for a crack (dismantle to check everywhere).

Could also be wrong estep (take Bowden off, cut filament after extruder, extrude 10cm and mesure to see if accurate)

Or maybe a partial clog.

Also check your flow settings in slicer.

Got one of this for about 2 years and it is working well. Did you try to adjust spring tension? Also, 20$ is too expensive for those. They cost about 10$