I'm always brainstorming ideas and I am someone who likes to tinker with things. Browse classifieds, buy/sell, etc... I currently have a solid paying job but do not enjoy 56-84 hour weeks. I want to start up a business for myself with potential to only work for myself in the future.

My question for now is:

Could I pick up good condition free items and donate to goodwill with potential to be $10,000-$20,000 worth of write offs from there or is there some certain cap? I would like to possibly have a professional business name to sell/part out some items so that I could write off my vehicle's mileage and other similar things. (Show little to no profits for this "business" while working my normal job. Looking for a nice write off, sorry for the ramble.