Is it legal to sale a complete working kit of imp?

I have few people very interested in my last electric imp project.
they wish i’ll sell it for money.
ive read in the wiki its under GPL and open source license.
Im not looking for making $$$, but all the parts & assembly do cost money and efforts.
If I offer my own built model of something, based on imp, is it legal?

You will have more involved than just the open source part. Not sure where you are located, but there are some liability issues in the event something fails and there is structure damage and/or injuries. I guess selling it as a “kit” might help you slide by some of the sticky points, but make sure the design is tested fully and you purposely create problems to see how the imp handles them. Any failures should result in a safe situation.

As mlseim says, selling a complete product often has liability issues (especially in your case, as this is an AC device and if someone wired it up wrongly they could hurt themselves).

As for the imp - if your customers were ok with individually signing up as imp developers, copying the code into their planner, etc, then they can replicate your product as developers.

If, however, you wanted to do an app to control this with built-in blinkup, and not need your customers to sign up as developers, then you’d need a commercial agreement with electric imp. This allows you to enrol devices, which associates them with your firmware out of the box, and gives you access to factory consoles, firmware rollout features, etc.