Tradify's UK pricing is per user, per month: Lite is £34, Pro is £37 and Plus is £44, with a custom plan priced on request. The page doesn't say whether that's with or without VAT. It's month to month with no contract, and every plan has a 14-day trial of all the features. Lite covers quotes, invoicing, scheduling, card payments and a sync to Xero, QuickBooks or Sage. Deposits (Tradify calls it progress invoicing) and timesheets start at Pro.
WorkPaid has no subscription. Sending quotes and invoices is free. When a customer pays through it, WorkPaid takes 2.5%, capped at £500 a quote, and you can pass that on to the customer. Card processing is separate with both tools: Tradify's page doesn't state its rate; WorkPaid's is 1.5% + 20p on a UK card through Stripe, or 0.5% + 20p (capped at £5) when the customer pays by bank.