If you're a frugal shopper, this Topshop Romper will fit the bill. It's a fail-safe choice, while not very expensive. Another strong contender for your wardrobe is this Topshop Jumpsuit. While the price of this piece is rather reasonable, it will surely attract a lot of attention.
If you're looking for something in between pricewise, why not opt for these Topshop Boyfriend Jeans. While the price is very reasonable, this item is an easy wardrobe update. You might also want to take a look at these Topshop Slim Jeans. It's an attractive option both price and quality-wise.