I use the infra red TN2 for thermometer... as ive got 30 odd reps I cant afford to keep buying loads of digi thermometers for each of the vivs... although some people say theyre not too good ive found it pretty accurate.
Hygrometers I wouldnt know about as I bought some expensive ones on livefood a while ago for my royals.
I got a digital thermometer from maplin I think it was ten quid or near enough. It measures both inside and outside temps and the wire on the probe for outside temps is long enough for most eventualities. Ebay do combined hydro and thermo ones but you will still need another thermometer for the cool or hot side. So I went for the maplin thermometer £10.99 inside/outside temps (hot side/cold side) and a hydrometer from home base for £2.99 and all works well.
Looks good enought to me, and cheeper than a lot of places. Do you need to have an account with them or can you just order them as a one off? One thing to do when you have actually bought your thermometer is to check it. You can do this by borrowing another thermometer from a freind for a couple of hours and placing both probes in the same place but in differnt situations ( i.e get ambaint room temp from both thermometers then put in heated viv and wait a bit, then compare readings. Effectivly you are calibrating them against each other.