Fancy macro lenses are the easy way to do macro. However, you can accomplish similar feats with cheaper methods. Mostly, extension tubes. The farther the lens is from the sensor the more magnification you'll get, but at the expense of depth of field and the focal point/range may be difficult to work with. However, it's a lot cheaper. A cheap set of extension tubes will cost about $12 and give you a lot of flexibility with how much extension you want, but you'll have to deal with losing aperture control and autofocus. More expensive tubes will give those features back.

Fancy macro lenses are the easy way to do macro. However, you can accomplish similar feats with cheaper methods. Mostly, extension tubes. The farther the lens is from the sensor the more magnification you'll get, but at the expense of depth of field and the focal point/range may be difficult to work with. However, it's a lot cheaper. A cheap set of extension tubes will cost about $12 and give you a lot of flexibility with how much extension you want, but you'll have to deal with losing aperture control and autofocus. More expensive tubes will give those features back.

It's worth pointing out that if you don't have a sufficiently sharp lens then having more MP won't help much. Here's a video ( http://www.youtube.com/watch?feature=player_detailpage&v=SVKcY4IZ5Ag#t=321s ) where they're comparing two similar lenses on the same camera body. Notice that when they zoom in one is better than the other. This is a result of the lens and more MP won't help that.

I'd look around for some cheap macro solutions (mostly lens reversal and extension tubes) before you decide you need to spend a bunch of money on the super-duper 5:1 lens.