None of us can accurately assess your personal financial situation. You'll have to figure out for yourself if you can really afford it. Getting into this 'sport', you'll quickly discover it's a money pit. In addition to bike cost and yearly insurance premium, you're gonna spend $$$$$ on full protective gear (helmet, armored jacket/pants/gloves/boots), tires, maintenance, the modifications you'll inevitably want, or more likely the 'better bike' you'll be saving up for and the mods for it (btw, $700 ain't gonna get you much bike -- and it'll probably require some TLC $$$). Don't forget about life and health insurance. It helps to learn to do your own maintenance - saves money in the long run, but you do have to invest some cash in quality tools. Oh yeah, take the
MSF Basic Rider Course, no matter what it costs (some states are free, some charge $200+). You said you have no riding experience, so PLEASE take the MSF class, for your safety and the safety of those who share the road with you.