Tess, this issue is not uncommon, but it definitely is something to pay close attention to whether your foundation is block or poured concrete. I am a general contractor, and have specialized background in foundation repairs.
In part the particular problems you may experience will have a lot to do with the soil conditions in your area. Sandier soils have better natural drainage (holding less water) and therefor less foundation problems occur. Soils with a heavy clay content shrink and heave with rain and dry spells, causing lots of costly problems for homeowners to deal with.
I would suggest that you have a reputable home inspector take a look at the home before making any decisions. Be sure to get one that will enter the crawlspace and inspect the entire foundation from the inside; many inspections fail to cover this thoroughly enough.
You should be looking for any signs of heavy dampness or standing water in the crawlspace, and for any signs of motion or movement in the past such as broken mortar joints or visible tilting of the foundation wall.
I personally prefer a solid concrete foundation wall, however, a properly built and maintained cinder block foundation is no reason to pass up a good home.
The most common factor which leads to damp and/or failing basements and crawlspaces is too much water next to the home. Look to see that there is good drainage around the entire house. The surrounding ground should slope away from the home, and there should be no signs of mossy-type vegitation growing on or near the foundation. Be sure that gutters and downspouts are in good repair, with at minimum a "splashblock" at the base of each downspout. If a normal level of moisture in the soil near the home is maintained and remains fairly consistent, you should have no problems with a properly built foundation of either type. Add water....and you've got problems.