What is most likely the lowest spf sun tanning lotion one can use to prevent skin cancer and still obtain a tan for people with light colored skin?

Be cautious: The most common forms of skin cancer are related to sun exposure and the resultant cellular damage from uv light which has long term effects on the skin. Therefore, any exposure especially in people with a more fair complexion can be harmful. To reduce your chances, you should limit exposure time and high intensity (midday), use a good physical sunblock at least 15-30spf and reapply it often.

Spray tan: If you really feel the need for a tan, use a spray tan and don't skimp on protecting your skin from UV radiation. If you have light skin, you likely burn easily and are at a higher risk as is.