You need to moisturise. Exfoliating would help and I would recommend it to anyone who doesn't do it, but moisturising alone should be enough if you can't afford a body scrub as well. (you can actually make your own body scrubs really easily, but I won't go into that now unless you want to know)
A good way to moisturise is Body Shop Dry Oil Spray, which costs £6 and is really good. I don't use it every day and you need to allow a while for it to soak in before you get dressed, but it gives your skin a lovely softness and a radiant look. I especially like it because often find body lotions leave residue or make your skin look dull.