[Dave20046]

if you google (would do it for you but I'm posting from my phone) mortgage calculator either Bbc or money saving experts site has one. you can also work out what rate would wipe you out-15%s not quite as bad as you'd think.(but still crippling!)
mse also has a overpayment calculator, like Bri says big differences can be made. obviously dependant on the loan but £50 a month could reduce the loan term by around 5 years (20% of the average term).

my dad bought his first house in the late 80s for less than £30k he did it up himself and sold it a couple of years later for around £80k -sickening!