There are definitely $100 grinders recommended in this sub (Baratza Encore and Capresso Infinity are both just over $100 and can go on sale)

https://www.amazon.com/Baratza-Encore-Conical-Coffee-Grinder/dp/B00LW8122Y/ref=sr_1_1?ie=UTF8&qid=1465874028&sr=8-1&keywords=encore+grinder

https://www.amazon.com/Capresso-560-01-Infinity-Grinder-Black/dp/B0000AR7SY/ref=sr_1_2?ie=UTF8&qid=1465874043&sr=8-2&keywords=capresso+infinity

Beginner filter setup

• Home burr grinder
• Travel grinder (fits inside aeropress)
• Goose neck kettle
• Aeropress
• Scales

This is only for filter coffee. If you want to do espresso at some point I'd recommend upgrading the grinder to Precisio/Virtuoso.

Burr grinder $129

Porlex grinder $35

Kettle $99

Aeropress $35

Scales $43

Total $306