You don't have to go far these days to find a retro frock without breaking the bank. For example this 1940s Midi Dress from ASOS ticks both the budget & vintage style boxes.
Vintage-inspired fashions are becoming more accessible for those who can't splash their cash so liberally. The dress is cut to a typical 40s style with a sweetheart neckline, flattering ruching detail, a-line skirt and puff shoulders with button accents, while the floaty viscose fabric in wintery teal adds to the overall vintage aesthetic.
A snip at £42 from ASOS online.