It depends on your budget. 3rd party lens manufacturers also make decent macro lens at a lower cost. I have seen a used 90mm Tamron macro lens (older generation) for sale around $200-$250. In general, a used Sigma, Tamron around 100mm focal length cost around $300 plus or minus.
I do not mean extension tube are bad. They are good for what it intend for. However, I do not think they are as good as a dedicated macro lens in terms of image quality. But it is generally cost less than a dedicated macro lens.
You may also take a look at a 100mm f/3.5 macro lens that made by Cosina. (You can find the same lens under different brands such as Vivitar, Promaster, Phoenix. I believe I just saw one under Tokina as well on
ebay). The lens cost a little over $100, but you need to make sure the lens shipped with the 1:1 adapter. (without the adapter, it can only do 1:2) From what I read, this lens is quite good optically, especially for the price. But build quality is not that good.
This is the Flickr group of that lens (
Flickr: Cosina 100mm f/3.5 Macro). You should be able to see some examples there.