HOUSTON -- You've seen the ads at various stores. They state that hundreds of generic prescription drugs are just $4 for a 30 day supply or $10 for 90 days. 

Stores including Walgreens, CVS, Kroger, Wal-Mart, and Target have developed a variation of these programs.

"You are better off going with the generic $4 program rather than going to another pharmacy and paying full price,” said Dr. Sujit Sansgiry.

Dr. Sansgiry said people can see significant savings for a 30 day supply of medication.

For example, the antibiotic Amoxicillin, at a regular pharmacy might cost approximately $12.95 without insurance. But through the $4 program, the savings would be $8.99.

Amoxicillin is only one of the drugs on the $4 program. The beta blocker drug Atenolol is also on the list and you could save $1.95. And with Metformin, which is an antidiabetic, your savings would be $11.49.

These $4 and $10 programs are often better than your insurance co pay. However, the savings are costing the smaller pharmacies.

“We have had a large amount of good patient-pharmacist relationships broken by these $4 programs,” said Shailendra Gupta of Southside Pharmacy.

Sansgiry said even the big stores are losing money, but the advantage they get by offering $4 prescriptions is that customers buy other items while they pick up prescriptions.

Top Generic $4 Drugs

Lisinopril - ACE inhibitor
$7.95 average price        $3.95 savings

Amoxicillin - Antibiotic
$12.99 average price      $8.99 savings

Levothyroxi - Replacement hormone for thyroid gland
$9.76 average price        $5.76 savings

Hydrochlorot hiazide - Diuretic
$5.45 average price        $1.45 savings   

Atenolol - Beta blocker/blood pressure lowering agent
$5.95 average price        $1.95 savings

Metformin - Antidiabetic
$15.49 average price      $11.49 savings

Tartrate - Beta blocker
$15.49 average price      $11.49 savings

Ibuprofen - Analgesic
$14.93 average price      $10.93 savings