Definitely worth two dollars for any SW GM with a little time change up the campaign to fit his own. Or to use with Mars SW.
Five dollars would probably be too much.
Although titled Rebels of Mars there is little to do with the Rebels.
A small force of Earthmen have shown up on Mars and are entangled in Martian politics, love triangles and slavers. They aren't the lead characters either. The PC's are mercenaries hired to find someone that has run afoul of the Rebels. We don't even run into the rebels until the last two adventures out of five.
There are some vague possibilities for further adventures for the rebels, but these seem to be merely two or three sentence hooks not real plot points.
Character motivations, plots and plans are not fully discussed until the end of the book in the Dramatis Personae section. However, the adventures keep referring to these motivations, plots and plans throughout the campaign.
With only 5 adventures PCs are not likely to advance more than 3 times. As a campaign/story arc it is very light and requires a lot of work on the part of anyone wanting to use it as something meatier.