Copyright is cheaper than the trademark. Copyright is a $35 filing fee with the government, but if you want to make sure it's done right you can use a company like legal zoom. That may cost an additional $100-200. Or if like me you get their premium business package when forming your company, you get 1 free copyright per month. Though you still have to pay the government fee. For our trademark it cost us over $500 and is a very long process (6 months). But again, it depends on if you want to make sure it is done right, or just wing it and do it yourself.
You automatically have a common law trademark and copyright on your brand and products, but if you federally register them you get instant protection in court. In some cases $100,000 minimum in damages if anyone tries to use or copy your work!