start with strips...you can get em for under 5 bucks and they do the trick...
i've been using them for 3 grows now and soil is so forgiving that you as long as it's between 6 and 7 on the strips you're fine...that's the cheap-o way i've spent 10 bucks and it's done me fine for now...
but if you got the cash, go for it! i can't wait to get me a pH/ppm meter, just couldn't justify the speak right now