Anything cheap will be inaccurate after a few uses and not really worth the effort. If you can afford it the Halfords ones are great and stay accurate for ages, they're not cheap but worth the investment IMHO.
The deflection type pic above are ok but they do require a steady hand and Sharp eye I use norbars trutorqe range pricey but worth it as I'm always using them a few times each week if your on a budget save a little and get a halfords one you won't go far wrong with its life time warranty
That is far too innaccurate for anything on a bike. You really need a dinky little 1/4" drive jobby with calibration 0-20 Nm or thereabouts.
Something like this cheapy; http://www.chainreactioncycles.com/Mode ... elID=11142
the only problem with the halfrauds jobbies is they don't sell one that measures below 10nm. A lot of the stuff that needs to be torqued on a push bike requires values around the 5-6nm range hence I'm still looking for one thats measures from 0nm upwards so thanks for the Chain Reaction link, didn't think to look there
Norbar trutorqe 0-20nm will set you back £70 cheaper if you shop around taylors in Lowestoft is the cheapest I've found but only takes cheques or cash though