One thing you should always look for in a trowel is a strong, solid blade. Steel blades will last longest.
The greatest variety will come in the choice of handles, where comfort takes priority. Chances are good you will wind up with more than one trowel in your gardening bag.
But it's the soft grip handles with flexible gel that makes these tools a joy to use, especially when digging requires force. $8.95
Gardeners are at high risk for carpal tunnel and arthritis, but this rarely stops them. Thankfully there are many new tools coming on the market to keep us gardening longer and in less pain. The Wristsaver Trowel is one of them. It supports your forearm and holds your wrist at an upright angle. It's awkward at first, but you get used to it quickly. There's a knob on top, so you can use both hands for added strength. Around $19.00
For the traditionalist, they still make the classic wooden handle - green metal blade trowel. This one has a carbon steel blade and the hardwood handle is weatherproofed. I've had one for about 11 years now and it's in great shape, despite regular abuse. They say it's tanged for knuckle clearance. If they hadn't put that in the description, I would never have thought of it. So I guess it really is tanged. 25 year guarantee. $20.53