Rock Shox XC 30 TK Coil 100mm 26 Inch QR 1 1/8 Inch Rim/Disc Fork 2015
The XC 30 TK has 100mm of travel, external rebound adjust and is a great entry level XC/trail fork. It's versatile too. You can run rim brakes while you save up for disc brakes since it is compatible with both rim and disc.
I picked one of these up at my LBS a couple of months ago to replace worn out forks of my sons entry level trail hardtail. It is a great shock for the price, and is all one would need for recreational riding.