Where to get wood?

I would love to make new ledges for my three chins, but the only safe wood (kiln dried pine boards) that I can find are two inch thick (!!!) boards from Home Depot. I've used this for ledges, but I find them to be much too thick and heavy. I'm looking for something and inch or less, preferably. If there are any common places that provide these sizes, please answer below! Thanks!

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Shannon