The only vaporizer I’ve tried was a home-made one, made from a light bulb =P
It works surprisingly well, and I was sad when I dropped it one day :O
Google it if you want to try a vape out before shelling out 50+ bucks.

Those vapes are not worth the money. You can find much cheaper and more effective ones online. I’d get one of these if you don’t wanna spend the big bucks:
http://www.grasscity.com/eagle-bill-s-shake-and-vap-pipe.html
http://www.grasscity.com/aroma-therapy-super-vaporizer.html

Vapes are fun, but I prefer water pipes. Bongs are great, and the water filters out toxins (but not all of them).
If your aim is avoid ALL toxins from your medicine, then edibles are your best route.

Also when vaping, the weed is dark brown and really dry/crumbly when it is done. You’ll definitely be able to tell.

Hey, you’ve made the right choice to use a vaporizer for you medical purposes. I own both the Vapor Genie and the Magic Flight Launch Box. They are both great vaporizers.

When using a vaporizer, you know your herb is spent when the amount of “vapor” coming out of the vaporizer is significantly less than when you began. Vapor is similar to smoke, but it is thinner and easier to inhale. You’ll know when your herb has lost most of its active ingredients because you won’t see or feel it in your inhale/exhales. Another indicator, as pointed out by Andre, is that your herb will be brown rather than the original green.

Both the Vapor Genie and Magic Flight Launch Box are portable vaporizers that are more for personal use because of the size of the “bowl.” Both can be used in groups but not as easy as some vaporizers.

When using the Vapor Genie there is a learning curve that has to be mastered. So you’ll have to teach your friends how to not burn the herb. It’s easy to burn the herb the first couple times you use the Vapor Genie. Especially if this is the first vaporizer in your friend group, they must be taught the difference between vapor and smoke.

The Magic Flight Launch Box is much easier to use in comparison, unfortunately it’s also more expensive at $100 compared to the vapor genie which is only $55. Overall, I find that the MFLB is a better vaporizer, and feel more comfortable recommending it to a new medical user. The down fall you’ll find with the MFLB, is that while using it with friends, you need to keep your batteries charged. The MFLB only comes with two batteries, which is enough for about two sessions.

If you’re interested, there is an article that goes into more depth comparing these specific two portables.

http://www.magicflightlaunchboxreview.com/vapor-genie-compared-to-the-mflb

If you are concerned about price I’d take a look at the Vapor Genie, but be aware that it is more difficult to use compared to most vaporizers.

http://www.vaporgeniereview.com

If you want vaporizer that is still on the cheap end, but is easier to use then the vapor genie check out the MFLB.

http://www.magicflightlaunchboxreview.com

I personally think you’ll be more happy with the MFLB if you can keep those batteries charged! But if vaping with multiple people is your biggest concern that I would consider checking out the No2 vapir vaporizer. It will be bit more expensive, but it will work better with a more “party atmosphere.” You won’t need to teach anyone how to use the vaporizer, no chance of burning!