I have the whole SquareUp Register system as my POS system so card payments are built in. I can also take payments on my phone if I'm away from the shop.
I pay a little bit more per transaction (1.75%) but that's all I pay, no machine rental etc...and I get the money next day, even over weekends.
Also intergrates with Xero accounting software.
https://squareup.com/gb/en/hardware/register