How would his dress (asking specifically about men) have differed from that of someone lower or higher up on the social scale? How would it have differed from what people were wearing in England or France around that same time? Were there any significant regional variations in costume between different parts of British North America in the middle of the 18th century? I am mostly wondering about the 1750s and 1760s.
First I should break down some basics on what makes up an outfit, I think. The average man, fully dressed (not talking about casual laying around the house or doing heavy labor), would start with his shirt and stockings. The shirt is long and tucks into the breeches to serve as a sort of full-body underwear. Sometimes trousers are worn instead of breeches, but as of the 1750s/60s they are worn by sailors and laborers. Generally there's some sort of neck "tie", whether a kerchief, cravat, stock, etc. Over this is the waistcoat (we'd call it a vest in modern terms), which may or may not have sleeves. Then comes the coat or jacket. Generally, coats are the longer skirted styles, while jackets are shorter. However, just like today I can tell you some things are definitely a coat, others a jacket, but there's a grey area in between. Add in shoes, hat, cold weather outerwear, accessories, etc.
The biggest difference in dress for anyone in the 18th century comes in the fabric. The cost of clothing is mostly in the cloth to begin with, so that's really where all of the adjustment is. To have a plain suit made (breeches, waistcoat, and coat) is generally a consistent cost based on the number of hours it should take. Tailors are very common, whether in the city or traveling about to less populated areas, so there's not much opportunity for them to raise costs above an affordable rate. Some places, like England, even have caps on how much they can charge (based on what the Tailor's Guild decides). So, if your labor is the same regardless of class, it comes down to the fabrics and supplies. Wool, silk, linen, and cotton are the four main textiles of the times period. Wool is by far the most common for mens suits, but that comes in a HUGE range of prices. For that reason, you would see a plain wool suit in nearly every Englishmans/Americans wardrobe. You could add silver or gold lace (wide braid) around the edges, paste stone buttons, or any number of expensive details if you wanted to up the price and the impact as well.
The regional differences are very occasionally cultural (the Quakers for example), but more often have to do with weather. Someone in the Carolinas won't have the same range of garments as someone in Massachusetts or England, no different than today. In the Southern colonies, linen and cotton would be far more common, as would very lightweight silks and wools. A heavier wool broadcloth suit would be a staple in colder climates. Unfortunately, I can't give you too many specifics on "average" people just because clothing is so very personal. Some people care about clothing and are willing to spend far more of their earnings on it than others. That merchant may have a suit of the same cloth as a blacksmith, it's just that the merchant has many more, or doesn't care about fashion and the blacksmith does.
For more reading I'd recommend Textiles in America, The Dress of the People, and What Clothes Reveal. There's also a thorough article on men's summer attire in the warmer climates by Neal Hurst. I wish there was more out there about men's historic fashion, but it's still a relatively unpublished field.