All doulas set their own fees, so all doulas charge different amounts as there is currently no regulation or recommended amount. Many doulas offer complementary services and therapies to support you throughout pregnancy, labour, birth and postnatally. Some doulas may offer complete birth or post-natal 'packages', some may charge expenses only.
Almost all doulas offer payment plans and sliding scales to suit all pockets and financial situations. It's well worth viewing several doulas' websites and contacting them directly for further information. Almost all doulas will offer payment plans or a sliding scale for fees, so do 'shop around'.
Generally most people caring for the birthing family want them to feel supported and cared for by someone that they know. Someone who has faith in them and the process and can follow them through the entire journey - through pregnancy, birth and the early days. Mostly our healthcare system isn't set up to provide this kind of continuity so in the main our maternity care teams are in favour of families being able to access this support via the doula.