Gunpla Building Community

You don't even need Gundam Markers. Regular water-based acrylics often work fine. Just make sure that they stick to plastic. If they're marked as "multi-surface" you're usually fine.

For instance, this and this were both primarily brush-painted with acrylics from Michael's, and the parts that weren't were done either with a set of metallic acrylic markers that I bought on Amazon or a 10-pack of paint tubes that I bought at the dollar store. Just make sure you thin your paints before using them and apply multiple coats. Fortunately, you can thin them with ordinary tap-water.