By all means get a dynamic mic, as you will need an external power supply if you use a condenser mic.
For a really good, but inexpensive mic, you might try Samson Q8.
My favorite mic is Sennheiser E945, but it's a little more money.
Both those mics are Super Cardiod, which means they are very directional and will not easily feed back.
The Sennheiser has less handling noise.
I have probably 20 mics laying around here and most of the modern ones, $100 and up, are very good.
P.S. You will need a mic cable with a 1/4-inch jack on the male end, as the 700 does not have XLR input.