I buy cheap chuck steak all the time and it is much improved by aging in the refrigerator. The thick "7 bone" shoulder cuts are especially good. Try to buy the ones that are already firm and a deeper red color, not the lighter, floppier, more "raw meat" looking cuts.
1. Get it out of the shrink wrap and that sanitary napkin thing as quickly as possible. The latter is a bacteria hotel.
2. If it smells at all off or is a bit green, give it a rinse with lukewarm water and pat dry. Blue is a better color, especially if it just smells slightly cheesy and not rank. It's probably O.K. to hit it with a little salt or spice rub, although I usually don't until it's dried out a bit.
3. Put it on a rack on a plate or roasting pan that will fit in your fridge. It needs to dry on both sides. I suspect a light wood rack would be better than metal mesh, because wood kills bacteria whereas metal seems to encourage them. But mostly you just want to maximize air exposure.
4. Mine is a batchelor fridge, a 1950s era thing with good Freon action and a balky thermostat that tends to keep it very near freezing. Also it houses little but beer and beef. My yuppie sister's fridge probably wouldn't work well--it is way too crowded, probably not quite cold enough, and ironically probably has a broader spectrum of bugs cultured in all the exotic yummies and leftovers. Use the one out in the shop.
5. When the top starts looking a little dry and dessicated, flip it over and let the bottom have a go.
6. Eat whenever. If it gets a little rank, cook it rare and see if the dog will eat it (mine at least prefers it cooked, and cooking seems to prevent re-emergence).