Southern charm USA / universal studios

Hey!

I’m about to head over to the USA on the southern charm trip (part of the road trip USA). After I leave the trip I’m heading back to Orlando for a few days to spend more time at universal studios - I’m trying to decide if I should pre purchase my tickets now online (approx $290 USD) for 2 days. Or wait and get them on the day. Another option would be seeing if I could buy them off the topdeck tour guide - as it’s advertised that they cost $100 USD a day through topdeck (I’m assuming because of the group discount) - but I’m not sure if these tickets are for the one day only or if can be used a few days later? Does anyone have any experience or advice?

I have no idea about this.