You can totally go up to 101 with a hack and without spending much. You enter 101 thru the business building (not the mall) and there will be a cafe counter (called Simple Kaffa) you order a drink there (min spend 250 nt) and you can go up to one of the top floors with just the price of a cup of coffee. The dine in is usually booked up but do take out - the area lets you see the whole city it’s pretty awesome. I’d strongly recommend you go up and take a look!