adding additional product (or service) to the existing product

[daniel123]

Hello, please I would like to know if it is possible to add an additional product (or service) to the existing product,
for example :
We have a conference which costs say 400e, and now in checkout I would like to add a checkbox (f.e. yes or no type thing) with sentence :
*""Dinner 22.5.2017 with the social program = (fee per person) 37,-Eur ""*
-And if someone click on "Yes" (or I will attend possible If there will be just one line in checkbox) , then the price would raise by those additional 37e .. so 437e
-And if is checked "No" (or nothing checked) , the price would stay the same.

THanks a lot for the answer and help!

[jjk]

Probably possible with the 'Related Products' module.

[balai]

I think that a normal custom field can do that.