As far as free options that will both compress and write to DVD, as others have pointed out, options are a little limited in my experience.
Technically, you could use your Mac's Disc Utility and a couple of free apps, but it's a bit of work and your options are limited. The free "DVD Imager app" can make a UDF disk image from a VIDEO_TS folder. It't a pretty simple drag-n-drop situation. Then use Disk Utility to burn. Or if you want an interface to handle the burning, the free "Burn 1.1" app will do the trick.
The problem is, this doesn't get around your compression issues, which you typically encounter when burning the 7G original DVD MTR'd content onto a single-layer 4.7G DVD. Although it you only rip main titles you might be able get under the single-layer size restrictions.
If you find all of the above a bit of a head-spinner, Popcorn 2 is a Universal app and will do all you need it to do in this case (compress and burn). And it's cheaper than Toast.
Anyhow:
DVD Imager:
http://lonestar.utsa.edu/llee/applescript/dvdimager.html
Burn 1.1:
http://burn-osx.sourceforge.net/