I'm looking to do a one-shot to try my hand at DM-ing. In addition to this, I'm also building the setting and objective by myself as well. I've decided for everyone to be level 5 and have built encounters around it, however I want to be more accurate to the equipment a level 5 group might acquire. I'm assuming they have the starting equipment from level 1, plus whatever types of items they can be reasonably expected to acquire in 4 levels. Obviously, characters with magic items will fair much better against monsters with certain resistances against non-magic items.
I want everyone to roll characters just before the session starts. How do I handle their starting equipment when they are above first level (specifically level 5)? Do I give them gold and let them buy directly from the PHB? How much then?