No worries. What did you get?
IMHO SCX are better than Scalextric as they are a bit slower with less grip so you can slide them about. Also, when junior does launch one into the wall it should survive.
Check out the Goldstar link that I posted earlier as they often have them on offer.
SCX Ferrari 360s are very good as they are short and wide so they handle very well. The longer ones like Aston Martin DBR9s are a bit tail happy which makes them good fun for adults but irritating for kids as they crash easily. SCX NASCARs are good too as they are almost unbreakable and look cool.