Inexpensive DIY decorating solutions for a damaged concrete slab? Pea Gravel?

My tiny urban "backyard" is nothing more than a scaling, uneven and moisture-patchy concrete slab (with a 6-8 inch high border) and a fence surrounding it. Next summer I'd like to fix the patio up but being on a tight budget, my options are few. I was thinking of covering the slab with pea gravel, but I'm concerned that the pea gravel could cause moisture problems. Would pea gravel be okay? Any other suggestions?