Not really. You just need to check with your state to see if you need a license, and figure out your best situation, whether it be self-proprietorship (and you file with your personal taxes) or an LLC for limited liability.there quire a few schools of thought on this issue
Yes for sure you can be a non profit in the seed business as I have chatted with several operating under this from the seed savers exchange in the past. It is not to say the gov may not change the laws as to which types of businesses can apply for the status but i have not seen it done yet. My sister does a non profit on the side raising farm products from her farm and also has a general contractor business license. Like I said you may have to change some wording on the price like calling it a donation or shipping fee per packet. Talk with a business attorney on it as each state may have different rules but the fed ones will be the same over the whole USA.i don't believe non-profit status is going to be applicable to your situation, even if you are not making a profit.
it's all going to differ from state to state and county to county... in general each level of the government (local, state. federal) is going to want their cut...
it's likely that your county and/or state have some sort of template online for setting up a business entity. that is the case here in virginia at least.
in some cases setting up a business entity will be as much for your own personal protection from liability as it is for claiming your income correctly.