Bit of an out-of-the box idea: make large-ticket purchases overseas where you can claim a refund on sales tax, then you are effectively cutting down cost of travel by making savings on purchases you would have made anyway.
In Europe, the sales tax would be VAT, in Australia GST etc.
This works best for destinations where you can claim the refund DIY without the need for agents. For example, GST refund at Australian airports is quite straightforward.
Your savings may vary... if I understand correctly there is also no sales tax in Delaware for example.
In the same way, taxes aside, you might find some things are just cheaper thanks to local pricing.