Many vegetarians and vegans wonder if they should take an iron supplement. If you are worried about whether or not you have low iron, you should start out by getting a blood test. This will show you what's going on inside and let you know if your iron is low or could use some help to bring it back up.
If you are looking for a vegetarian iron supplement, you can check out Active Iron High Potency. It's been created to help you absorb more of the iron, it's high potency, and it's kinder on the stomach (some iron supplements can bother the stomach). One thing to note here though is that this is suitable for vegetarians, but not vegans. The capsule itself is vegan, but the ingredients inside does contain whey (which is milk derived), so it is not vegan. You can find Active Iron High Potency capsules here.
You can find numerous vegan iron supplements, too, here is a link to some of them.