I'm seeing cracks in sheet rock and have doors that stick.  I'm guessing it's time to have someone take a look at the foundation (slab).  The house was built in the '70's so it probably needs a bit of TLC.  

Has anyone had this done lately?  What was the cost and how long did it take?  Was it much of hassle to get it done?   Any companies to recommend or which to avoid?  Do you know of any companies that give free estimates?  Thanks in advance for your help.

Not what you want to hear, but it could be anywhere from a $5000 minor inconvenience to a $30,000 you want to burn your house down pain in the ass.

Our house in Houston had foundation sagging due to leaking pipes that caused a cavity under the foundation. It cost us $17,000 to repair the pipes, backfill the cavity, and have a foundation company pressure-pump a solution under the slab to raise it back to level. We had insurance that covered damage to the foundation caused by water, you should call your agent and see what they say your policy covers.
 

I had my house done last year (in the Victoria area). 31 piers cost me 10.5K

Wow!  Bet that hurt.  If I may ask, what were you seeing as far as effects from the slab shifting?

I had my foundation repaired a couple of years ago for $4500.
Basically the garage had broken off of the house, so the piers were under the garage.
Unfortunately the repair broke the sewer pipe under the house.
They had to dig under the house to repair it.
That costs me another $3500.

Yep, writing out that check stung quite a bit...

We basically had the whole house shifting, settling on both ends (2 3/8"). Cracks in the floor tile, cracks in the sheetrock around doors and windows throughout the house etc etc. They had to drive piers every 10' around the whole house plus two where they had to jackhammer holes through the patio, two in the garage and one in the driveway. All in all it was pretty painless (besides writing out the check). It took them two days, a crew of 6-8 showed up early in the morning and they dug holes all day, the next day they drove the piers and leveled the whole house...I haven't had any trouble since...It really is nice not having to worry about it all the time.