The cheapest suggestion I could think of is one of them cheap styrofoam ice chests. They hold about 5 gallons, and could make a thin plywood box to go around them to protect the styrofoam. Not as convenient to carry as a 5 gal bucket but would work and not expensive.
Does anyone know of a company that sells a styrofoam liner for a 5 gallon bucket? I checked all over the 'net and can't find one. I have 4 different size battery operated aerators, and a couple of aerators and pumps I can plug into the wall to save batteries. But when warm weather gets here, I'll need an insulated lbait bucket that holds at least 4 gallons to take care of bigger baitfish like shiners and chubs. I already have a 10 qt insulated minnow bucket and several of the 2 gallon pure styrofoam buckets, but they're not quite big enough for shiners.
Someone told me Grizzly Jig Company sold liners for 5 gallon buckets, I checked their catalog and they don't now.
Festus I just wanted to give you an update on this. I just got back from Bass Pro fishing sale they have going on right now. They have a styrofoam bucket liner with a lid for a five gallon bucket for 5.99, its really nice. I plan on getting one next week, I only had enough money for some line and a few other things I needed today. They also have a nice backpack tackel bag on sale for 29.99.
Look into a cooler, hell you can get a bigger roll around cooler with two lids for around 25 or 30 bucks, then buy a Mr. Bubble aerator and mount it on the lid that doesnt pop up, That is what I would do, JM2 cents. Then least You would have a decent cooler and a bait tank all in one.
If you are still looking for a 5 gallon bucket with liner, go to EBay and search under Hunting Bucket. There are several listings for this at 19.99. I have looked for months and this listing and a listing on Amazon for a Personalized Fishing Bucket are all I have been able to find.
There is another I have found, with built in air pump, but is is like $80.00.
I have one I have used for years and will never use any other bait bucket. With air pump I have kept bait alive for several days in Texas 90+ days.
I have insulated them myself before with 1 inch thick foam board, very cheap for a sheet and it will do multiple buckets, cut a circle to fit the bottom add a little silicone and stick it down, then cut a peice of foam board as tall as the inside depth of your bucket,cut it into 1 or 2 inch strips then simply put the strips in and glue them with silicone all the way around the bucket, as easy or fancy as you want, if it gets damaged you can replace the damaged section or just reline the bucket, a 4"x8" sheet will cover alot of buckets, save a tiny bit of money and give you something to do on a crappy day when you can't fish,and you can insulate any bucket, I like the 7 gallon ones myself. those square buckets like kitty litter comes in are great for bait buckets too and even easier to insulate, let your imagination roam and have fun.