Is It Worth It?

Whut Brian said, tbough I'd go as high as 2 cents per stamp. $300 is too much but $50-100 would be reasonable, assuming about 3000 stamps as someone else estimated.

Put the onus on the seller to show why it is worth more than $100--ask for photos of the first two pages of major countries. Ask for a ballpark estimate of total number of stamps. The seller should be willing to work for his $300.00. If he can show that it contains 6,000 stamps or that it has some early stamps from some countries that are worth a few dollars, then it might be worth paying $150 or $200 or even more. But the seller needs to show that. If they are mostly common-as-dirt stamps and you are just starting out, a collection like this could be a good way to get started and a lot of fun but don't overpay for your fun.

If the seller doesn't cooperate and offer more photos or an estimate of total numbers, make a low offer around $100 max and if the seller refuses that, don't worry--you will eventually find a 3000-5000 collection of common stamps for $100 or less.