Calming our yellow lab/english setter during the day ......?

we leave for work in the morning and leave our dog at home by himself. He is crated and he cries/barks when we are not at home. The neighbors have started to complain to the (condo) association because of his excessive barking. We could consider taking him to doggie day camp, but we do not have the funds to do that now. I've also heard about giving him Benadryl, but we need to talk to the vet first. What do you guys suggest? We will not get rid of the dog!