I think mine was about £30 but if you can afford a Leica Distometer (the cheapest ones are about £100) I I really would recommend it. The Ryobi one I have is not much use for measuring outdoor distances as it only uses the lazer to shine a dot on to the surface you want to measure to, but it actually measures the distance by using a sonic beep. This works fine indoors but outdoors there is often too much interference for it to work accurately.
I have used the Leica distos and they actually measure with the lazer so they are supposed to be accurate up to about 100 metres.
If you have around £300 - £1000 to spare, the Leica bluetooth models are excellent. They will beam dimensions straight to your laptop, pda or phone. If you use them in conjunction with bluetooth enabled cad software like Powercad Sitemaster, the software can actually draw elevations or floorplans semi-automatically while you measure. See link to "Give Me Power" who sell Powercad Sitemaster. Michael Axon, the guy that runs this firm demonstrated the system at my office and it really was impressive, but expensive. The Sitemaster trial will let you save though so it is worth downloading and having a play.
http://www.powercad-sitemaster.co.uk/
edit: Its worth having a look on ebay too, just found this http://cgi.ebay.co.uk/LEICA-DISTO-LITE-D5-LASER-MEASURE-DISTANCEMETER-IN-CASE_W0QQitemZ350122746172QQcmdZViewItemQQptZUK_Measuring_Tools_Levels?hash=item350122746172&_trksid=p3286.c0.m14&_trkparms=72%3A1301%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318