What to wear to a casual reunion after weight loss on a budget?

[CharlotteCChapel]

If you were going to.a reunion later in the year. It's likely to be in the social club where we had our leavers do so nothing formal
What sort of items would you buy. Ive lost weight due to illness. So dress to impress but not try hard.
I'm 170cm and a small 16
No stupid prices

Have a look at brands you like on Vinted? I like Nobody’s Child, Kitri, AYM and there’s loads on there. I got a dress for £15 that’s £190 brand new!