I'm not sure you can find one for less than $200, and those types are the early transistor or MOSFET design are are purely constant current. I've been looking for over 3 years for one and finally settled on the Array eload, see that thread.
Until then I made do with 10x10 100 watt resistors than I could mix in series or parallel combos for 100 ohms or less to get close to what I needed for a current drain. Quality power resistors cost between $5-10 each, so that alone will run $50-100, not including other hardware.