Participation in the Society for Creative Anachronism, like many hobbies, can cost as little as you can afford or as much as you like. Most people who join the SCA are on budgets and you can participate without breaking the bank, especially if you are patient and gather things over time. If you rush in and try to buy all the cool things right away, then It can get expensive.
Local meetings are usually free to attend, but some local archery practices or fighter practices may be held in locations where you need to contribute a couple bucks to help the group rent a space.
If you are budgeting to attend an event you can break down the cost into a few basic categories: gas money, clothing, site fee, camping gear, spending money.
Gas money – this depends on where the event is. Some are right down the road, some might be a 16 hour drive away.
Clothing – you are required to wear an attempt at pre-1600CE clothing to attend events, but most people start in basic tunics or dresses that cost around $20 or just borrow something from the loaner clothing.
Site Fee – The site fees are collected to allow the non-profit organization to rent the facilities we need. For normal weekend events they can cost from $10-20 with a $5 discount for members. Week long camping events, called wars, can have site fees from $80-100. Some events will also have feasts or evening meals that often cost around $10 for a multi-course dinner attempting to replicate a medieval feast.
Camping gear – If you are going to a camping event then you will likely need camping gear, but you can also use modern tents, sleeping bags and cook stoves.
Spending money – There are often people selling materials people need for crafting or finished goods at events, but there might also be food vendors on site for larger events. If you are not camping but day-tripping an event, you might also have to budget for food on the road.