I would like to know which is the cheapest and most accurate – any suggestions would be wonderful!!!

"Best" is subjective – what do you need at the moment?

ancestry.com can be BEST, so the annual subscription is worth it. Censuses are historical documents, as are military records, draft cards, what have you. Others' family tree research accuracy varies. Even mine have been found to have typos.

rootsweb's resources are free to the user, excellent. Local histories and biographies are not always accurate but for the greatest part they're meant to be. The message boards are searchable, as are the email list archives.

familysearch.org. The collection of filmed historical documents is excellent and if found online, still free. I understand that will be changing in some cases. The user-submitted family history databases can be gems, or rife with outlandish errors – caveat freebie.