Karion is right walking is good for you, start of with a stroll around the block and make it further each day, either by distance or time out walking. It is lovely in the weather we have at the moment. I have done a fair bit today and its free, great for your bum, thighs and calves.....so whats holding you back.
By the way, you should have put this in your diary section then I could have answered your questions all at the same time.