if you are looking for factory Rotax parts, all dealers are supposed to sell at the same price.
I’d suggest a local shop that will provide service AFTER the sale.
It doesn’t do much good to get the parts and struggle with how to install them.
Maybe the kart is not running right and a simple jet or plug change is needed? If the local shop that you bought from is at the track they will help you, the internet shop can’t.
That said, Acceleration Karting in Vegas has an excellent web site and ships FAST.
Curtis and his staff have always helped me and they also support the club I race with as well as being a sponsor on this web site.