I already have a dedicated macro lens. A Canon 100mm F2.8, but I wanted to test close-up lenses on my Canon 70-200 F2.8 IS. The best option is with no doubt Canons own close-up lens 500D, but at $150 it’s a bit over my “just-for-fun” budget.
First I purchased a Fotga +3 close-up lens for $5. The combination with the 70-200 was so bad that cropping and interpolating is much better. (However, it performed much better together with my Tamron 17-50. Guess it’s better on shorter focal lengths ) Then I ordered a Green L close-up +2. At the pricetag of $7 I didn’t expect to much. This lens is as I understand it equivalent to the 500D in terms of magnification. To my suprise this combination also worked much better.