If you had to buy two outfits/dresses, one for a rehearsal dinner and one for a wedding, what would you buy?

I'm assuming both events are semi formal, and my budget is probably $100 or less for each dress. Temperatures will be in the 50s.

I saw all the same people at a wedding last weekend so two of my go-to winter semi formal outfits are out I'm a size 6 or 8 petite.