You can buy gpus at many sellers with a loan and pay it back in 1 year.
Nearly nobody whout give you this advise for mining crypto, but it is possible.
How much solar do you have? I doubt you can run 3 rigs full time, but if so
it might be an option to look for a partner to do this.

In case you basically have nothing, no hardware and no knowledge in mining
you wont find one. In this case.... better forget it.