Home foundation repair is a costly necessity; it isn't like a mere sagging bed frame or a stuck window, and it isnt a repair to be put off. The worst problems most home - owners face are the how and the how much: how to do it, if you're handy with do - it - yourself projects (admittedly some repairs are beyond the abilities of most), and how much it will cost.
The first thing to determine is the extremity of the cracks you've noticed in your foundation. Notice also the location, which will make a difference to the ultimate bill: is it in a corner, at the center of the foundation block, or does the crack extend to the walls, and perhaps even up those walls?
If there is a wall crack, is it horizontal or vertical? Horizontal indicates your house, and its walls, have a lateral drift, and that can be expensive. A vertical crack is much less problematic, and can be just the house settling (and a home repair you can definitely do on your own).
Finally, what's the reason for the crack a flood, a fire, an earthquake or just poor foundational soil? If its the latter, the problem will obviously recur; if the former, you may be able to pay repairs through insurance claims.
Once you've figured these out, its much easier to estimate the cost of foundation repairs. Yes, its going to be expensive, but you should be prepared for the bottom line.
A crack in your concrete, up to several feet, that is central to the foundational block and does not extend to corners or walls, is usually going to cost between $400 and $800. The materials alone, for concrete, should run around $200 to $400.
This is also the kind of repair that you can often do yourself, with the help of a consultation with an expert. You can find one either at your local Home Depot / Lowes or similar home repair business, or online (there are experts who give cheap, often free, advice for such repairs, as well as Q and A forums that perform a similar free service).
Is the crack a major one, extending to corners and/or running up a wall? This is much more serious, and can run you between $20K and $25K, as there is very little a do-it-yourselfer can do for a foundational compromise (the range of cost depends on the extent to which the house rests on the damaged area).
You will definitely need a contractors service for this concrete foundation repair; visit as many as you can who are local, and get estimates from each before deciding. If possible, choose one as near to your location as possible; there will be a smaller bottom line if the transportation costs are lower.
This is also the reason you determined the specific dimensions of your foundational crack; most contractors have a sliding scale of repairs that they offer for cracks that are central, extensive, compromising walls, etc. Its easier if you know the extent of the damage before visiting the contractor.
Now, face that home foundation repair with confidence; at least you know the bottom line.