Need help getting ph and tds/ec/ppm pen

I need help selecting ph and EC/TDS/PPM pens. Doing Hydro gro and normally just eye ball it (sometimes would turn out good). this time bought really nice beans and dont want to waste my money. I hve max of $100 bucks to spend since i blew 250 for 250 watt hps and mh set and inline fans and dwc rig (diy). Dont know what to get in this field NEED help some links and i want a nice one but wont cost me arms and elgs even though these testers mean a good grow or a bloody amazing grow. Need some help

I do not know what you mean by eyeball?
I do not use any pens but with your budget save for a good ec meter.google:wich ec meter hydro or dwc ppm pen(etc)
I use General Hydroponics ph kit.piss yellow for hydro.It's cheap and effective.
http://www.htgsupply.com/Product-General-Hydroponics-pH-Control-Kit.asp
or if u have ph up and down
http://www.htgsupply.com/Product-pH-Test-Kit.asp

Eye ball it as in see how the plant react. estimate my PH since i know that in my house the ph is 6.8 pretty much all the time have water softner and then a seprate RO on that as well (friend has ph tester) so i normally just add ph lower for each gallon making it 5.8. Would like a reader for ec/ppm/tds reader and nice ph reader but under $100 since that is all i have left for this grow budget.

I hear Hanna and Millwauke (spell?) might be good.

I am looking around and finding alot and have a question. can you find a reader/tester one that does not have to calibrated or calibrated so often?

I actually have one of these so i guess i can use that and it reads at 124 on avrg since i remember using this. Now i just need a PH monitor/ tester and NaCl 324 (if i recall) to calibrate my tdd meter