Should be £7.59 but you can apply a voucher from the amazon listing which takes £2.60 from the price.
4.5 star reviews. Nice handy tool to have.
You can get it without Prime but then you'll have to pay delivery which will negate the saving so not really worth it.
Bumf from amazon product description:
FAST RESPONSE AND HIGH ACCURACY: Chuck seals quickly to valve stem for quick and accurate measurements. Fell comfort in knowing your tyres are performing at their best to get you to your destination safely.
Range: 100 PSI = 7.0 Bar = 7.0 Kg/cm² = 700 Kpa.
ERGONOMIC DESIGN: Fits the hand comfortably, and features a soft, non-slip surface for a sure grip. Improve fuel efficiency & road handling by optimizing tyre contact with the road.
EASY TO USE -Our compact tyre gauges are lightweight but sturdy, easily applied to the tyre with one hand for accurate readings. Slip your tyre gauge into your glove box or backpack for storage. The tyre gauge will automatically shut off within 30 seconds after use.
BACKLIT LCD DISPLAY: Digital display shows exact reading instantly and clearly, eliminating the guesswork of analog gauges. The Tacklife tyre gauge is easily applied in poor light conditions anywhere, anytime day or night.