If you prepare the area for lawn yourself and sow grass seed instead of laying turf, you'll save a whack. If you're unable to do the main prep yourself, most gardeners ( gardening companies) will do it, but make sure they don't get too fancy with you. All you need is some basic labouring for that, so perhaps family members or friends would help out.
imho , it's like saying ,"I'm looking to buy a car, how much will it cost"
Pansy - I actually did laugh out loud at that! Amazing what a couple of well-chosen emoticons can do.
I'd agree Hosta - it's too variable to give a good estimate.
There's some good advice here oxymoronic - a little bit of research into prices in your area for various projects, and who would do them, is really the best way to go. That way, you can make a decision more easily, and perhaps look at different ways of achieving your aims
It can be frightening how much a small job is
Aside from what others have already said about it being impossible to give you a clue I'd suggest the following:If all you're looking for is clearing out old stuff, paving and turfing then I'd suggest that rather than looking at "landscape gardeners" and and calling it landscaping that what you actually require is some muscle and hard labour.That tends to come cheaper and it may well be that because you're on a limited budget and know what you want that it would be better to have a look in your local shops and facebook adverts etc to find a couple of general labourers/handymen and get quotes for a couple of days work. Or else tell them what you want to spend and ask what they can do for that fixed price amount.