Yes, it is worth getting.

Graphics are considerably better than the NES. The game selection isn't as huge but there are many fine RPG's on the system as well as 3D glasses AND games on cards {ala tg16}.

I wouldn't pay more than 85$ for a system in good condition.
I managed to score a SMS1, SMS2, controolers, hookups, 4 complete games, pretty good working condition for 10 dollars Canadian.

85 is like an ebay price.
If he doesn't know what one looks like, he could end up buying some cardboard box with the word sega written on it at a pawn shop that sells it as a Master System.
Master system 2 wasnt very good, whomever got that one was severly ripped off, unless you got a model 1 and you can actally play all the 3d games, missile defence 3d was a great game for its time. The 3d glasses in general was great, plus the my hero game card.
Buy a model 1 with light phaser and 3d glasses if possible. And of course missile defence 3d and you'll see what i mean.
Good luck finding the model 1 with the light phaser and 3d goggles. Its very very hard to find that complete. You are lucky enough if you find the 3d goggles. The 3d goggles go for 100+ complete alone since they did sell that seperately at one point.

And out run 3d is one of the holy grails of SMS. Very hard to find that one and some TEC TOY games from Brazil.

If you find those, you don't pay too much for em since they can be VERY costly to a collector.

The sell that thing new down here (Brazil). But not the original model. It's one newer, rounded model, that has no 3D glasses plug.

But I think the obscure game dumps have piles of old model 1 SMSes lying around. And boxes fulla old games.