I’ve worked on one with nearly 5000 products, and including variations it has over 7400 products total. I’ve also worked on a site that has over 35,000 orders as of today ( selling phone accessories ) and gets at least one new order every minute or two, 24 hours a day. No problems there.
WooCommerce runs within WordPress, so your contraints are the same as WordPress. If you expect high traffic, don’t bother with shared hosting as it is rarely ever geared towards heavy traffic. Get a dedicated server instead, and don’t skimp on the RAM and CPU power, especially if you’re running the Web site and database server on the physical computer. And … when you see dedicated server pricing and it seems high just keep this in mind: You have to spend money to earn money. In nearly every situation, response is usually dictated by database server performance… not Web server ( Apache, Lightty, Nginx, etc ) performance. DB servers need to be tuned, and tuning needs to be done by someone that knows what they’re doing, not by someone fiddling around willy nilly. Make sure you get a hosting company with a proven, knowledgeable support team.
Bottom line: WordPress scales if a person knows what they’re doing. Thus, WooCommerce scales if a person knows what they’re doing.