Just a notice, but if things are just edits of pre-existing tiles, sprites and the likes of that, being paid real money (so reborn rupees do not account for that) for them can get both the commissioner and the commissioned in trouble since it's basically art theft (as in making profit off someone else's work) and therefore illegal! If you want them to make edits out of pre-existing graphics that come from the original RSE/FRLG games, then it's a lot safer to pay them back in a different way, just not with money as it can possibly get you in trouble with the law.
If the tiles/sprites are completely made from scratch (have some form of proof saved that you actually did make them from scratch, just in case) then it's fine though, but do notice that there's a very thin line between the two when it comes to the style the artist will be working in. It's safer to work in a style that is similar in a few ways but still different from the RSE graphics if you want to actually pay someone for the graphics.
Either way, I wish you the best of luck of finding someone suitable for the task c: