Does anyone have a suggestion on the best value for price for a tour of these three locations.

I would like to use a tour guide/group put some of the options people mention are several hundred dollars a person and this is out of my price range.

Are there any economical tours?

Anyone with any experience on romaexperience.com and their tour?

piericci.it for the underground colosseum. not sure you need a guide otherwise.
Get yourself a good guide book.

Agree with Jerry on this one.

Most group tours of these 3 Ancient Rome sites together will cost around 55 - 80 E per person.

If you book through Piericci, you can do a Colosseum tour (either the regular tour or the 3rd tier/underground) with their guide and then do the Forum and Palantine on your own.

We enjoyed our semi private tour with dark Rome tours.
$513 for 4 of us.
Included arena floor, underground and third tier.
Also included forum.

Probably the cheapest tour is the Colosseum's own tour which can be booked through Pierreci. The entrance ticket is 12€ and the tour is 5€ for a 45 minute tour. On Pierrecit's website, the info is in Italian only, but here is a list of tour times in English.
http://www.pierreci.it/home-page/it/...e-singoli.aspx

You could also just rent one of the audio guides for 5.50€ or d/l the Rick Steves tour from ITunes (free).

The 12€ entrance ticket include the Colosseum, Forum, Palantine and should be good for two days.

I did the colosseum tour yesterday, and it was great, detailed enough, interesting, and wanting to answer all questions. The guide was enjoying showing us the colosseum.