Don’t think only about the jacket and trousers.

Think about:

Suit + waistcoat + shirt + neckwear + shoes + accessories + alterations.

If you’re hiring, some of these may already be included within the package. If you’re buying, they may all be separate.

The groom may also decide to spend more on himself than on the rest of the wedding party. For example, you could invest in a made-to-measure suit for the groom while hiring coordinating suits for the groomsmen.