I had ordered a pair of shoes about a month or so before 17 Tammuz. They are a semi-handmade item, and it turns out that they the item was back ordered because of a recent sale. I was initially told 2-3 weeks, but it is taking longer than that, and I worry that the shoe will be manufactured during the three weeks. It is a returnable item, and an item kept I stock.
TThere is no problem with having something manufactured for you or to buy new items during the 3 weeks, as it is only an issue during the nine days, (for Ashkenazim or the week of T’bav for Sefardim).
If the item is very special and would require a shechiyanu then it would apply even during the 3 weeks, however we don’t make a shechiyanu on shoes, so it isn’t an issue, and it is permitted.
O:CH 551-6, M:B ibid 45.