Here is a list of sites to help inspire.
Airbnb
Great for experiences, both in person and virtual. As well as accommodation.
Amazon
Great for almost anything mass produced
Etsy
Great for home made items from individuals and small businesses
Firebox
Unusual gifts
Fiverr
Custom work commissioning
Groupon
Great for find a deal, especially for local or delivered food and drinks
Photobox
Great for custom gifts
Not on the Highstreet
Items (including custom) from small businesses
Yappy
Custom gifts for pet owners