what tds meter is acceptable?

Ok so, my friends and are about to start a DWC grow, and having come to the conclusion that we really should get a tds meter, we are now having some confusion when it comes to what tds meter to get. The basis of the issue is price.

A simple search on ebay comes up with these pages of tds meters: (the first page is a comparison between the ever popular bluelab truncheon meter that I see in every online hydro retailer, and a cheaper truncheon meter. the second page is just a lot of cheap meters)
truncheon, Yard, Garden Outdoor Living, Militaria items on eBay.com
tds meter, Yard, Garden Outdoor Living, Pet Supplies items on eBay.com

Now it seems there are two categories of tds meters:
Cheap ones in the 20-50 dollar range,
and the ones that are regularly seen in online hydro shops, over 100$

I have seen advice from both sides of the issue. Some say that cheap ones don't do the job, but then I saw filthyfletch, someone who obviously knows what he's doing and is experienced, say that he bought one on ebay for 30 $ or so.

Any opinions would be greatly appreciated, would save us about 100 dollars or so actually.

thanks

I have the cheap tds-3 that ships for $20-30 off ebay and it works fine for me. Only complaint is that it's not waterproof, so if you drop it in, it's done. other than that no complaints, seems accurate enough. If you don't have an electric ph meter, I highly suggest you get one. The more often you check/ adjust the ph and ppm, the better.

bump......

I used the Milwaukee SM802 and it kicked ass. On the expensive side though, i eBay'd it for like $120+