Food Allergies Treatment

My 5 mo old son has been on a hypoallergenic (very expensive) formula since age 6 weeks due to a diagnosis of lactose intolerance and milk allergy/sensitivity. Now that he is on solids he seems to tolerate milk products well and I am attempting to change to a regular formula to save money. Has anyone else tried this? Been successful? Today he is getting half and half and seems to be doing fine. I know what to look for with the lactose intolerance, but the milk allergy diagnosis was shaky so I am not sure what to look for.