There are small lights to put in the yard. They collect electricity in the day and store it in a battery. At night the battery powers lights to light the sidewalk. In this case power stays in one spot.
Some houses have solar cells on the roof. In many cases the solar cells help power the house. Maybe the house uses 1000 watts. If the cells make 500 watts then you need only 500 more from the power company. But if solar is making 2000 watts and you need only 1000 then the extra 1000 will be pushed back to the power company and it will help your neighbors. In many countries the power company will pay for your extra power.
If you're asking about a larger-scale utility system, then you may be able to feed that PV power back. Most of the time, it's worth more to simply use the power rather than attempting to sell back.
You could, honestly, probably find one cheaper. I don't know how willing you are to play around with an inverter. But if you are into putting in some work, I think finding a used one is a good step in a more helpful and useful direction most of the time.