The price, including service charge is the best we can offer

From a grammatical perspective, this sentence should read as "the price, including service charge, is the best we can offer.

Nowadays, English speakers tend to omit the second comma and keep the first one. It is grammatically wrong but is commonly used, so no big deal.

The first comma cannot be ommitted.

不可以，这是省去which的非限制性定语从句。