As a rule, it's difficult to proofread one's own work reliably: Having a second pair of eyes on the job is always helpful. Sometimes it's even more difficult to find that second pair of eyes, unless one is willing and able to pay. I'll be paying extra for the second set of corrections, but not enough to break the bank.
iUniverse has plenty of ways to break one's bank. The company does many things I like, and a few I genuinely don't like. Yesterday one of their marketeers called from the noisy call center in the Philippines, inviting me to take advantage of a service that would get my novel reviewed in Kirkus Reviews and two other publications. Sure, a good Kirkus review can provide an invaluable boost to a book's sales. Sure, it also costs $3,499. Does that money guarantee a positive review in Kirkus? I do have scruples about such things.