As any 18th c. American, you would actually be encouraged to buy things from England: the purpose of the colonies was to produce raw goods, like timber, cotton, furs, iron, etc. and send them to England, and with the credit buy finished goods in return. Colonial crafts were discouraged. That discouragement was hard to maintain, and by mid-century there were some colonials making their own hats, casting their own brass candlesticks, rifling their own gunbarrels. But still, the quality of imported goods could often be better than what was available at home. For a wealthy planter, a sale of tobacco or a cargo of planks would create a credit that could be put into a London bank, or at least put into the books of a merchant doing business in England and the Colonies, and a written signed note could be sent to the bank or merchant to direct payment, when there was a purchase to pay for.

George Washington wanted a nice fowling piece, or shotgun., for John Parke Custis. He wrote to John Brazier, a London gunsmith, and gave him the specifications, and it arrived in October 1767, likely paid for with a draft on a London bank. Could Washington dicker, or did he have someone there dicker with Brazier over the cost? That we don't know. It cost him eight pounds eight shillings, which was more than twice the cost of one made locally. But it had silver mounts ( buttplate, triggerguard , etc) and a water-resisting lock, a quality which might have been hard to get in Virginia. London gunmakers had a high reputation, and likely Washington heard about Brazier, or saw one of his fowling pieces in the hands of someone else.

It was possible to have people shop for you. In 1785, when Jefferson became ambassador to France, James Madison asked him to get a watch from one of the fine Parisian watchmakers. That was seen by Washington, and appreciated. When Gouverneur Morris travelled to Paris in 1789, he wrote to Washington offering to "execute commissions" for him in Europe. Washington wrote back asking him to pick up a watch similar to Madison's. He enclosed a draft on a London bank for 25 guineas, saying he could send more if needed. Months later Morris wrote back: he'd gone to Jefferson for advice, who told him the maker of Madison's watch was a rogue. There was then an agreeable bit of shopping by Morris for the watch, being dissuaded by various Parisians that one maker was a rogue, another was out of fashion.... until finally settling with Lépine, thought to be the best, for two watches- one for Washington, and one for him. Presumably, when the watches were done, Morris brought them back with him.