Hard to say...LOT of choices. The Canon 100mm f/2.8 EF USM macro is solid and affordable, but not a "pretty" imager in terms of its out of focus highlight rendering, which has sharp, septagonal bokeh balls. I had one for years, and NEVER liked it, sold it earlier this year for about what I payed for it five years earlier.
The Tamron 90mm AF-SP Di is a great macro lens; better than the Canon in term,s of a "pretty" image and its background rendering. MANY available used, been made for years now.
Tokina 100mm f/2.8 ATX-Pro is another good value. I say buy a macro lens used, not new. Many are bought, tried, then retired, later traded in, or sold at a huge loss. So...look for used macro lenses. I have seen literally 30-year-old macro lenses in LIKE NEW, barely-used states (and have bought two of them, dirt-cheap).