The product key is VPMV-7PYX-VTY6-RTY6-6VTY.
This code for the SIMs 3 Fast Lane Stuff may or may not work. Despite posting the key here, you should understand that the information may be found to be invalid on grounds of licensing terms. Products such as games and all software have product keys for a reason. These product keys are meant to ensure that everyone buys the product legitimately rather than finding a free download and accessing it via an old key or falsifying a key with online options.
Morally, it would be best to buy this software from a legitimate company and obtain the product key through normal means. It is possible to buy products second hand because someone might be done with it and want to sell it. If this is the case, you might consider calling the company to explain you purchased the software from a second hand store. They may be able to issue you another product key without your having to pay for it.
If you purchased the product legitimately, the product key should be on the cover for the item. If the cover has been lost it is best to call the company that produces SIMs 3 Fast Lane Stuff to find out what can be done to issue you a new product key.
The above key being placed online has probably been used at least once. Depending on how strict the company is regarding their software you may find it is not usable. Furthermore, it could be a fake key to tag those who try to use it as using illegally downloaded software. To avoid any issues with legality it is far better to pay for the software you have purchased in order to get a true product key to use with that software programme.