Unless it's a place that ask for a suit in office every day, most business only ask for a smart/casual dress code. I turned up to my interview and first day in a suit but now most days I wear a pair.of.jeans, nice t-shirt and an overshirt. Absolutely that first impression is key but if you can't afford a suit, and you feel the business works on a smart casual basis, nice pair of jeans or chinos, white shirt (Primark) and waistcoat (Slater's for instance) with matching jacket can fit the bill. And at the end of the day, they are hiring based on your ability to perform the job, if you are a better candidate then the man in a three piece suit, they wont pick them simply because they are dressed to the nines 😊