Hi Darrin,
In terms of getting good sound, mic placement and environment are more important than what recorder you use.
In general, any mic you use shouldn’t be more than 2 feet away from the interviewee’s mouth. And you want to be in a room (or place) where there is little or no noise ie: others talking, air conditioners, motors running, traffic, etc.
What type of mic you use really depends on where you’ll be conducting the interviews. Your budget is very limiting as even a basic hand-held mic like the ElectroVoice 635 is over a $100 dollars (a good rugged all-purpose mic, I might add). Lav mics will cost more but can also be better at rejecting background noise, esp. one with a cardioid pattern. You might look at used gear as it will serve you as good as something new and cost less.
Dave J