The real key point here is that we aren't accountants, or even we are, you aren't paying us and we won't represent you at an audit. How you use the information we provide is at your own risk.
As I take it, you are an employee of company A ("I work for a company that installs pools"). Pools that you build may come with options, including a particular accessory (a cleaning system) provided by Company B. Company B offers prizes and other rewards if you convince your customers (customers of company A) to purchase and install Company B's accessories.
This is a SPIFF, and is "other income", not self-employment income.
In reading about the history of SPIFFs, I find for example that Apple and IBM used to pay direct commissions to computer sales persons (employees of ComputerWorld, Circuit City, etc.) for selling their computers over competitors. Today we think of it mainly in the car industry, but we really don't know how many other companies might do this. The key concept is that an employee of company A, who receives a direct commission from company B in return for persuading customers to buy company B's product over a competitor, reports the income as other income, not self-employment income. I don't see that it matters whether company B is a manufacturer selling a tangible product, or whether company B is a service company that sells installation of a tangible product originally manufactured by company C. Company B gives you a reward but you are not an employee of company B.
(The situation would be different if you were an independent contractor working for company A, and you were subcontracting to company B to do certain work. The incentive from company B would either be a reduction in the price you paid to company B, or self-employment, either of which has the net effect of raising your self-employment income. But assuming you are a W-2 employee of company A, the reward from company B is a "SPIFF" and is other income but not SE income.
Turbotax assumes by default that box 7 is SE income. Don't change the 1099-MISC. Report as is, but answer the texting questions "No" (not like your regular job, not done with intent to earn a profit, not planning on doing similar work next year). This should put the money in as other income, not on schedule C.
However, you will likely get an automatic letter from the IRS tell you that you should have reported the income as SE income. You would need to send a detailed reply explaining why you believe this income should have been reported in box 3 and should not be considered SE income.
