Unless you have a special dvd player that can play avi files (they do make them, I have two of them), you cannot play avi files on a standalone dvd player. You can burn the avi's as data, and will be able to watch them on your computer off the disk. If you have one of the special dvd players, it just depends on if it can play that particular type of avi. They play several formats but there are many more formats they do not play as there are endless numbers of diffrent avi formats. Odds are if your player can play avi, you would know it. It would say something about being a divx player or something like that.
If your player is not a divx/avi compatible player, then you would have to convert them to standard dvd format to play them on a normal, standalone dvd player. While this is quite doable, it takes a long time, and dvd standard (which uses mpeg2), takes much more space. A 700 meg avi file will be a couple of gig mpeg file. You will have to use more disks than you planned, but its quite doable.
What software do you have (in particular, do you have nero)?
If you have nero, use the "make your own dvd-video" option in start smart. Add your files (however many you can get on one disk for the first project). If you add too many files, it will ask you if you want to reduce quality to fit. It really depends on the quality of the original avi. If the avi's are very high quality (like dvd quality which they probably are not), don't let it reduce quality, remove the last file you added. If they are your typical avi's, you could probably let it reduce quality once and keep adding files. It will let you reduce quality several times and keep adding more, but I wouldn't recomend it. The second time it asks I would say no, then remove the last added file. Then step through the next couple of screens to create simple dvd menus (hint, you can use screen shots from the video files for buttons and background), and burn it. I can find a guide if you like. If you do not have nero, look at these.
If you decide to try it, and wind up saying, oh my god, this takes hours.... Yea, it does take hours. Start it converting before you go to bed or something and let it run overnight.