If it's a legitimate business then yes you can write it off as a loss. I do it and I don't have a CPA. I use H&R Block tax software, it will walk you through all the steps and ask you question by question of what you can and can't deduct and will put everything you enter on the appropriate forms automatically. And it has links to YouTube videos if you get stuck. And every year they update with the new laws and new links to the videos explaining them in detail. I've been to tax preparers and they never ask me that many questions in that much detail and tell me what the new laws are.
For me the best way to do it is to run it through your tax software the first year when you are starting out and then make a spreadsheet in Excel with all the items you can deduct and track them the following years and save all your receipts. It's amazing how many deductions you can take if you keep track of them all. You can even deduct some meals, lets go to Red Lobster and talk about our snake business! 8) It's also good to talk to other business owners to see what they are taking as deductions.
However, you can't deduct expenses if you don't have it set up as a business in your taxes.
I also like to set up a business bank account with your business name attached (doing business as '...') That way if someone writes a check to your business name instead of your personal name you can actually cash it.
Personally I don't like retirement accounts like 401K, etc. Just too long term for me. It's like saying give me a hundred thousand dollars and if you make it to 65 or 70 years old you may or may not get all of your money back LOL. I'd rather have complete control of that money, I can double it in a few years easily. Or I'd rather use that money to pay off my debt. Maybe if I were debt free and didn't want to expand my business and was making a ton of money and had a tax problem because I was making huge profits then yes, I'd consider investing in the market. I would much rather invest that money in a business I know will be profitable than risk it in the market. Either way it's tax deductible.