It'll give you something, at least, for a minimal effort and cost, until you make up your mind what you really want. That way, you have plenty of time to research all your options, material & design. I'd guess you'll have several hundreds of dollars in either of your first stated options... you can build a very usable set of steps for, probably, under twenty bucks... and with some effort on your part, they don't have to look like something just thrown together. As I said, if you have a router, you can bull-nose the edges, and with an opaque stain you can make them just about any color you want.
If you do go that route, a bag or two of
Quick-crete or
Sack-crete to make a pad for each riser to keep them from settling too much would probably be be a good idea, too!
I suggested a stain, rather than paint, to reduce the amount of "slippery-ness".