It's tricky. From what I've read, you get what you pay for, so I've always opted for buying a lamp from a reliable source and haven't been disappointed. A quick search for your lamp RLC-032 shows the price is often $120-240 at reputable vendors (mostly towards the higher end.) Remember that not only could a cheap lamp die prematurely or have poor color, it could explode in your projector and damage it (make your you don't touch the bulb and transfer your skins' oils onto it when you install it.)
Reliable vendors:
http/www.projectorcentral.com/lamp-suppliers.htm
One online store also points out: "Many online stores sell just the bulb, without the housing, which requires manual installation by removing the old bulb and rewiring the new bulb into the existing housing. Projector Lamps America sells the complete lamp with the housing, so installation is quick and easy."
I'm no expert, but if you want a more informed opinion, I would post at avsforum.com in the projectors < $3000 forum. Good luck.