For Michelin and Mobil 1 patches, I'd say go straight to them. See if you can mail them a letter asking for whatever amount you need. If you can't find a mailing address, try going through their website.
My logic behind this is that they sponsor race teams and such, and you always see the sponsor's badges on their suits and uniforms. So they may have some lying around, they may even hand them to you for free.
