If you can’t spend much, this J.Crew Turtleneck will fit the bill. It's a fail-safe choice, while not very pricey. Another nice option is this Missguided Rollneck. While the price is not very high, be sure that this item will become an excellent addition to your wardrobe. You may also want to look at this Aqua Turtleneck. This item is not expensive either, but it will make a difference in your wardrobe.
If you can afford to spend a little more, you're in luck with this Turtleneck in stock and waiting for you. You most certainly will love this piece. It's also worth checking out this Courreges Turtleneck. This product is ultra popular and, just as importantly, not very expensive. And do check out this Tibi Rollneck! It's a very popular item and good value for money.