I have a running joke going with my DM that she's a witch or psychic. Often I'll ask her to guess something obscure and she'll get it straight away like she's read my mind. She occasionally plays the lottery and seems to win loads of small amounts or lucky dips whereas I win nothing (ever!). She'll mention she's playing out of the blue and I'll tease and say she just 'got a feeling' and should run with it.
Anyway a week or two ago she said she was playing and I normally join in (to highlight I never win and she does) but I said 'I won't tonight as it's a triple rollover and only two more to go until it has to be won so your odds are better if you wait'. It got to the fifth rollover and I bought a couple of tickets the day before and she got a couple too.
I checked my numbers and I'd matched four, normally just over £100 but because of the rolldown prize structure it was about 5x that.
My AIBU is that I told her I'd won and we checked her numbers, and I accidentally did the worst prank 
On one ticket I thought she'd matched three numbers, and I said, 'Oh, you've won £118!" (instead of £30) 
She'd actually got 2 numbers and the bonus ball which doesn't count and she got her hopes up and then saw she'd only won a lucky dip
I keep thinking of those horrible pranks you see that go viral where people are given a fake winning scratchcard or when they recorded the lottery numbers from the draw before and then the person is checking the numbers thinking they've won but they haven't. Even from a young age I thought it would be a brilliant prank if the other way around (!) but I feel mean now.
The reason I'm posting is I was hoping for some unusual or quirky gift ideas or things to do together so we both 'benefit' from my win. I love when an MN user comes out of the blue with something I would never have thought of. She'd hate a spa day, gifts often go unopened or unused because she wants to 'save them for best' meaning never use them ever and I actually got her birthday present this year purely down to a thread I read on MN and she loved it. What would you do in this situation? 