Like anything in life???? You get what you pay for... but you can always find a steal!!!!
More expensive vibrators... the best vibrator I've ever had was just under 70USD. And I've bought vibrators for 200SD price tags. I've oodles of luxury clit vibes that I'm disappointed with, a number of g-spot toys that were cheaper than some of the clit vibes that I'm disappointed with too.
Glass... I've not really seen a difference between the quality of the pricey and not so pricey ones.
Dildo's... have to admit I don't really collect these.
The best advice I can give, is look at your collection. Find people who have written reviews for those items. Read them. If they had the same thoughts as you, look at some of their other reviews for items they've liked.
Chances are, you might enjoy those ones a little bit more.