A crew-neck sweater is a sound investment in comfort and practicality. Style it with slim-cut denim or layer it over a button-down collar shirt and team with a midi skirt for the smartest take.
If you're not planning on spending much, your best bet is this Boohoo Crew-Neck Jumper. It's a great piece, while not very costly. Another strong contender for your wardrobe is this Boohoo Crew-Neck Pullover. While the price of this piece is not very high, it will certainly attract a lot of attention.