Survey incentives are completely legal, even in the B2B world. But there are requirements that differ by state and country, so make sure to check with a legal professional to verify that you aren't breaking any rules.
Can I offer a prize for completing a survey?
The use of survey prizes, also known as incentivizing, is a common way to get complete responses in online surveys. Survey creators offer an incentive (many times money or a gift) in exchange for the completion of the questionnaire.
Do survey incentives create bias?
The use of incentives, particularly monetary incentives, increases response rates to all survey modes [49], but if they are equally effective across all sample members then they are unlikely to affect nonresponse bias [50].