Well, the first part is to not expect to make a lot of money off this.
Since you bought these from a video store owner, I would expect that these are video release posters and not posters from the film release. video posters are generally only worth a fraction of a theatrical poster. However there are exceptions.
When you check a sales database, such as emovieposter, it is important to add the qualifier 'video' to the search criteria. Bruce is very good at including that tag.
If you plan to sell on eBay, you need to note video poster as well, or you will get complaints and likely judgements against you for misrepresentation.
I think I would bundle these into small groups with common themes, say Disney or 80's comedy. Be aware that packaging and shipping costs are significant. They eat into the final price people are willing to spend. Most dealers charge around $10-15 shipping for 1-20 posters, so you need to take that into account.
That leads into packaging. You need too ship in sturdy tubes. Anything less ends up with a high rate of returns for damaged posters. Never, never, never use the post office triangle tubes. I would suggest you read around this site for packaging issues and suggestions.
As for bulk sales, I would need to see a listing with conditions. Without that I am going to assume they are all junk posters, like the Care Bears II or Pauly Shore 'You're in the Army Now' which are even questionable as wrapping paper. Sorry if I am being too negative, but I really am trying to help. I have looked through several lots just like the one you describe and have passed every time.
