If you have a dollar store around they will often have something that will work. I like the carry out boxes from restaurants. Poke holes in the bottom for drainage or watering from the bottom. Cut a hole in the lid and tape clear plastic or Saran wrap over the hole for light and humidity control. Place in a plastic storage container from the dollar store to hold water.
The take out containers work good for stratifying seeds too.

I use old sheet pans from commercial kitchens (26" x 18"), but you can also find fairly rugged plastic or rubber trays for holding winter boots. Restaurant supply stores often sell used sheet pans, but try to get flat ones - they can be warped by improper use.

Many common household items can be used to start seeds in, the only requirement is that the trays the seds are in should have good srainage so the starting medium does not stay too wet. Many of us have two trays, one for the seeds with drainage holes and one that goes underneath with no holes so water will stay put. Seed starting trays should be about 2 or 3 inches thick, ie. deep enough to hold a sufficient amount of growing media, so many resturant sheet pans may not work (too shallow).

I've always used standard propagation flats for my seed germination (flats with drainage holes), then transplant them into cell packs also nested into the same kind of flats. I seed three or four hundred bedding plants (all kinds) into a couple of the flats, which are equipped with heating cables. Transplanted into cell packs, that's a manageable 10 to 12 flats full of plants. I use cell pack sizes of 36 or 48 cells per sheet. These past couple of years, all I can handle are 3 to 4 hundred plants.

I never water from the bottom but use a misting nozzle for the seed flats and a regular gentle nozzle for the transplants. Even seedlings and bedding plants appreciate fresh, oxygenated water moving through the root system.

I reuse both the flats and the cell pack units over and over, storing them clean and dry out of the sun.

Here is a link that might be useful: flats and cell packs

I use clear plastic salad green containers.

Got any restaurant supply stores nearby? The cafateria trays work great for watering purposes. Or even some old plastic picnic trays that are designed to hold paper plates & cups, etc.

Thanks for your responses! I wasn't looking for items to grow the plants in, I was looking for pans or trays to set them in so I could water the pots from the bottom up.

Thanks!

Polystyrene bins are good for large quantities, supermarkets often get salad leaves delivered in them.
I also use plastc trays like litter trays that I find.
Enamelled roasting dishes are good too.

You can also cut the tops off milk jugs & use them.

I use cat litter boxes--cheap ones that I buy at the dollar store. I put my little starter pots (yogurt cups, etc.) in the litter box, cover with plastic wrap, then I put the boxes on top of heating pads--I find those at the thrift store and take off the fabric cover.

I use Permanest trays which are designed for seedlings and will last over 15 years (if not stepped on)