Different pharmacies have the best prices on different injectibles. Do you know which brand you'll be on?
I've found that Freedom has the best prices on Gonal-F:
http://www.freedomfertility.com/fertility-medications/medications-and-pricing.aspx
Just as a reference point, I needed 450 units ($372) for my last IUI cycle. You may need more or less.
You can call around for various fertility pharmacies to get free quotes. Most have free shipping too.