With boffer swords it is too easy to get poked, hit in a sensitive spot, etc.
The SCA swords aren't much heavier, and with a little armour you easily eliminate the vast majority of possibilities for accidental injury.
Cost, well yes. SCA armour isn't very expensive (plus people sometimes lend stuff), but it is more so than boffer swords. Given that you are unemployed, this may be an issue. But I would ask an active member before deciding that you can't afford it.
Cheers,
Ben