For all my American readers, Wii Fit is released in the USA on Wednesday (21st May). If demand in the USA is anything like it has been in the UK, it will be extremely hard to get so get there early and shop around! Amazon.com is already out of stock.
For some reason, Wii Fit retails for $89.99 in the USA. The same product retails for £80 in the UK (equivalent to $135) making it 50% more expensive in the UK by a tune of 50%. I have no idea how they get away with this but it might actually be cheaper for British consumers to import Wii Fit from the USA (assuming Nintendo don’t use region locking on discs). Even after paying sales tax, shipping and customs duty it’ll probably still be cheaper.
Alternatively wait for the EU release on April 25th. As the EU is a free market, there are no import duties.
As an aside, for some reason Wii Fit uses imperial units (feet, inches, stone) rather than metric units (metres and kilograms) in the UK. I know most people still use imperial units in the UK but I come from the generation which is more accustomed to metric units. I wish this was a setting.