For sure sell yourself with a TN Visa, there's NO sponsorship required, just disclose the fee payment. I'm a Mexican who did the whole process by myself, no lawyers from the company required, and even though it's easier for Canadians since you just go to the border with the requirements and pay a super small fee, you get right in and can start working the next day after you come into the states. Assuming your profession is in the TN NAFTA list, you can get to work within a week with a TN Visa.