depends on what you want to portray.. and where you live there may be restrictions on what you can and cant do. what do you mean by "just not as good"? i mean they arent shooting bullets so accuracy means nothing
a full infantryman's kit (without musket) would be ranging from about 400 to 850 roughly, then you will want to upgrade your kit where possible, eg new trousers, you can buy really good ACW trousers for about 180-250.
with a musket, it depends, a pedersoli 3 band rifled enfield that can fire blanks is going to cost up to 2 grand.. but there are much cheaper options, they just arent as good.
not as well made. where are you from? how old are you? if you want to portray a rifleman, age matters, in america its generally 16 and over you are allowed to carry a rifle onto the field, in Australia, the absolute minimum is 12 1/2 with a minors permit.. and even when you are 18 you need your firearms license. not sure what it is in Europe.
but since you are in the 2te im guessing you are in America?