I can't even find the deal you're talking about on memorytogo.com--the all the iBook 512MB modules I see are at least $56, where the two standard "quality on a budget" RAM vendors recommended here, OWC and DMS, both sell the same for $49.
Even if I could find the deal, I probably wouldn't consider it worth the $10. Not that Memorytogo doesn't look like a decent business (their site is a lot more attractive than DMS's, that's for sure), but it comes down to three things:
1) 25% restocking fee on returns vs. 30 day money back guarantee.
2) In the unlikely case of warranty replacement you pay to ship the memory back to them, then they send you a replacement. DMS and OWC both have lifetime *advanced* replacement guarantees, and at least in the case of DMS I know they send you a prepaid mailer to return the bad RAM along with the replacement.
3) I quote from their warranty policy:
2. SYSTEM REVISIONS Revisions to your computer that cause memory that was working, to stop working, are not covered under our warranty and return policies. We only guarantee the memory to work under the conditions for which the memory was first sold.
The following customer changes are examples that will void our replacement/return warranty (this list may change without notice) [...] changing your firmware [...]
What that means is that if Apple releases a new firmware update that makes the computer more picky about RAM and it stops recognizing their modules (and this *has* happened in the past--it's not a total hypothetical), you're out of luck. When there's been an issue with this in the past, both DMS and OWC publicly stated that they stand by their products in the event that this occurrs, and will replace the RAM under warranty (though that, as far as I know, is not generally necessary since they both use quality chips).
