So many choices here, I'll try and get them all in one place!
In past years I have done the public goods game (also includes discussion of what I'm looking for in an induction activity) or the vaccine allocation task. This year I'm opting for a more lecture-style session on the economics of health generally, which hopefully allows me to address the scope of economics.
If I have time, we'll do some Policy Odyssey. If you don't have the time/budget to get cards, you can probably make your own. This year, you could also do some Election Economics. Tutor2U have helpfully posted all of their induction activities together in one place. Survive the Walking Dead is a staple of my first week, but would also work well for induction! You can find them all here. You can also repurpose Open Evening activities or use on screen games such as play Spent, Storyline, Gapminder, Tradle , Connect Trade, Pick 5 or FactQuest (a word of warning: my school firewall doesn't really like either of the first two, so check them out on your school network in advance). I know other teachers have used the Oligopoly game, the Efficiency vs Fairness activity, the Dialysis Machine activity or some form of the Desert Island Game as part of their taster days, so if you're looking for economics taster activities, you might want to take a look at those too. Another option would be to use these posters as a basis for a silent debate or other discussion task.
Some schools have a policy to set preparation work for Year 11s going into Year 12. I get them to read a chapter of our class book, Can't We Just Print More Money) and answer the questions below (I think it's legal to photocopy a single chapter of a book?!)
They also prepare for their numeracy baseline assessment. I give them a list of numeracy topics to revise if needed as well as a practice test with answers. I then set the other test in class in the second week of term. I also give out this leaflet with some summer reading recommendations.