I charge £5 -8 more depending on whether it's a plain colour or glitter/ombre but others on here I'm sure charge more.
My reasoning is, you don't need base coat, and I would've top coated with shellac or a gel topcoat anyway so all it actually is is the colour. Plus there's no cuticle work as it would already have been done before the acrylics. Hope this helps a bit x