Are there any good cartridges for under 100

There is always Grado as well, should be able to find a # of sites selling them just by typing Grado into any search engine.

Or you can even try Goldring MM cartridges start from $40 but to tell you the truth, I cannot still say that there are good cartridges under $100 in general. You can try Rega Bias for $125 listing.

The Audia Technica 440ML is an excellent cartridge and can be purchased mail order for $99 from several sources (J&R and the Needle Doctor to name a few).

Garage-a-records and Audio Advisor also have the 440ML for $99. This was a $229 cartridge. Must be on clearance/closeout.

The Grado GTE+1 is a pretty good cartridge that is DIRT CHEAP! It sells for under $40 but sounds like a much better cartridge.This cartridge is kind of "famous" Its the only cartridge to ever hold a class D rating in Stereophile!!
I have one with only 20 or so hours on it.
To help you break into vinyl,I am willing to send it to you to try out.If you like it its yours for $25.00 If you dont like it just send it back.You will only be out for the return shipping...let me know.