Godaddy sells .com domain for $6.95 (exluding $0.25 ICANN fee) if you use coupons so it is not much different from ipower. ipower cross- sells domains together with its main product, webhosting so can lower prices from packaging. Conversely, godaddy also cross sells it webhosting very cheaply together with its main product, domain.
I'd advise going with Godaddy for the much better service and the ease of transfering domains (as so many people use them). For Godaddy coupons, as mentioned above, check out forums.digitalpoint.com/showthread.php?t=302518&page=38 and remember to thank the wonderful people who post them!
It's called BUSINESS. Why can you buy a big plate of food in a cheap restaurant & pay big bucks for a tiny plate of food in an upmarket restaurant?
Domain registars need to earn money for themselves too .. so they sell their products @ different pricings .. dependent on how much they wanna earn from that sale