Whichever software you wind up using, I recommend it have the ability to produce files in the GEDCOM format. That's a common format for a lot of different genealogy programs and databases to be able to quickly share information.

At one point, Ancestry.com allowed people to download a past version of their FamilyTreeMaker software for a free trial (nearly full features for 14 days). You can then purchase the upgrade if you want to continue with the full features (or you can just reinstall the trial version to 'refresh' the features you've been using).

I also highly recommend doing a generation at a time, as completely as possible. Rootsweb may be a place to start, just to get some names. ("Trust, but verify" is the watchword with these records. Sometimes people have copied erroneous information from other sources, just because the names and dates sort of fit.) Also, keep in mind that with your female relatives, their death certificates will likely carry their married name and not their birth name (I found a couple of 'false positives' in the online records of my line like that).

Some states now have some of their Vital Statistics indices online. You can get certificate numbers and some basic info, then write to the state office for a certified copy of the full record. Some libraries may have duplicate archives on microfilm. They won't be 'certified' copies, but it's a starting point.

For example, Kentucky has birth and death indices from 1911 to present and marriage/divorce indices from June 1958 to present online. Prior to those dates you have to go to the county of record, if you can determine what that may be. A copy of the KY archives is in the Louisville Free Public Library, which is where I got copies of some certificates in my line. They're not certified copies, but I got a lot of information from them, and I can now write to the state office and pay a fee for any that I want certified copies of (proofs for petitioning for a grant of arms, for example). I can also point other researchers to these certificates to refute the 'false positives' I came across.

Good luck, and have fun!