If you are looking for an outfit without the expense, go to primark. The prices range, however you can get underwear very cheaply from about £5 for a set. Primark sell all sorts of women's and men's clothes, which are suitable for all sorts of occasions. Primark also do a large range of jewellery at cheap prices. They even do sweets at the checkout! Primark also do many different styles and their clothes are generally quite good quality; I haven't had anything rip or break from here before which is a bonus given the price tag.
Primark's customer service assistants are very helpful and friendly. If asked, they know where things are, and they can quickly serve you so you can get your shopping done quickly if you are in a rush. The layout of the store is tidy and organised, so it is easy to find what you want, and the store is also spacious so it is easy to wander around just browsing.
Primark also reduce items if they are damaged, and have a good January sale, of up to about 70% off! Their clothes come in a range of colours for a range of events. I would overall give Primark a high rating for a high street shop!