TDS and PH pens....

Hello people,
I'm on my second grow now and have been using General Hydroponics liquid ph testers. However, I want to invest in a reliable and accurate PH pen as well as a TDS pen. Can any of you make any suggestions, thanks......
Oh, btw, I grow indoor in soil if that helps...

our favorite auction website has both for under $20 ea. I recommend these for the simple reason if you don't have religion yet with maintaining the units, I.E. buffer storage solution and cleaning properly you are burning up a $50 dollar electrode (half the price of the unit, sometimes more) every other month from improper care. Once you have a cheap one under your belt for a grow, then u can afford a good Hanna 3-way meter and know how to take care of it. Make Sense? Just my opinion. And the cheap digital ones are/can be as accurate as the $150-up units. Buy a NEW one, I've been burned once already thinking i was getting a hell of a deal, when in fact dude had burnt up the sensor thats why he was ditching it so cheap. Learn from my mistake...

Yeah I was thinking of getting one of the $20 to $40 ones and then getting a better one later, thanks.