For the rear, something that takes AAs and bolts to a rack or mudguard. A while ago it would have been the excellent Infini Apollo, but now those are unobtanium, so you'll probably have to pay 2-3 times as much for something similar from B&M or whoever. A decent set of Alkaline batteries should last forever.
Not sure about fronts. You may have to botch a permanent fitting, which then complicates battery changes.
You say the budget doesn't allow for dynamos, does that include bottle dynamos? We've got an Axa on barakta's trike and it runs a Cyo + 2 rears just fine (no problems slipping in mud/wet on a Marathon Plus dynamo track). The cheap Basta dynamo lights have a conical beam, but work surprisingly well in all other respects. These sorts of things are astoundingly cheap if you buy them from the right Dutch/German sellers...
And also on the unconventional dynamo theme, Reelights...