Help me win the war on weeds. My entire yard is a garden and it's a major chore trying to keep the weeds and bermuda out.

What's a cost-effective pre-emergent like Preen that I could use that might be cheaper than Preen? I'm gonna go broke trying Preen my entire yard. There are unkept vacant lots all around me. They are overgrown with weeds that go to seed and the wind blows them in my gardens. I cannot keep up with the weeding! When I finish the gardens on one side of my house, the gardens on the other side of my house are all overgrown again.

Is there a more cost-effective chemical like Roundup? I find it's tough against bermuda, which keeps trying to creep in from neighboring yards. But again, I'll go broke using Roundup all season.

Do y'all buy in bulk at Farmers Co-ops or Farm Supply companies? How do y'all manage the weeds? I've seen professional gardens that are virtually weed free. How do they do it?? When I ask, they just smile and say, "With a lot of work." I cannot afford to hire staff to weed all this, so what suggestions do you have? Last year was the first year that it really became a major problem, and it's quite overwhelming.

And yes, I do mulch heavily. The weeds are all growing on top of the mulch. By the time I get to them, some are already tap-rooted thru the ground. HELP!