More exercise bike La De Dah at Argos ?

I am 57 medium build 5' 6" 11 st and have taken little exercise for
years. Both my parents have had heart attacks. I used to ride a bike
but dont want to now.

 I am planning to buy a cheapish 70 quid exercise bike in the Argos
catalogue for a 2 or 3 mile stint 2 or 3 times a week for a little
light regular leg exercise. I sit at a computer gooning around in
chatrooms for too long and my legs ache from my inertia.

Am I buying useless rubbish or am I buying something that will suit
the light demands I will put it to. Should I be looking at a device
which will cost hundreds and do lots of things I may not use. Maybe
you have other more lateral ideas, although I do fancy an exercise
bike as a light user. I have a proper bike but dont like rain and cant
carry mucho shopping on it. Loads of buns <G>.

Phil of Whittlesey Peterborough  England