@TheBoots
An independent jewellers or workshop would hopefully work with your budget and design. The first question we ask a client (after establishing what item or design they would like) is how much would you like/have you got to spend, and then source the best we can get within their budget.(or as close as possible)
With Tiffany you are paying for their advertising, reputation, name and branding, luxurious shops in prime locations, probably a glass of champagne etc as well as the jewellery