A good solution is to look for a package deal that includes various garments as well as any set up charges that may be incurred for your logo.
A common term is a 'Man Pack' and they often consist of the most popular clothing to cater for one person.
I would recommend the following items to start with:
Poloshirts - the most popular promotional garment
Sweatshirts - A great compliment to the poloshirts
Fleece Jacket - Great for those chilly mornings
Work Trousers - Completes the top to toe
Add baseball cap and a hi viz vest, ensure all items carry yourbranding and you have a complete branded uniform.
As many companies have minimum orders, by doing it this way you can build to a minimum quickly without having too many of the same item.