20 gallon long LED lighting?

I'm going to be setting up a 20L (12inch deep) I don't want to have a limit to what corals I can put in my tank but I'll probably stick with softies and easier corals anyway but I really don't want to limit myself in case I decide on something else later.

I'd like 2 different answers unless a single answer applies to both

1st what's a good LED option for what I want?
2nd what's a good cheaper option for what I want? (Cheaper not so cheap it doesn't work)

Thank you :)