Your local church is not going to function without it receiving some kind of income from its congregants on a regular basis. Most churches are probably 501-C3s, so they can use their money without paying taxes---so salaries, church upkeep and running, ministries to the pubic, are not magically being paid. So although the tithe is a part of the law, let's also know that giving unto God supports His church and gets us away from idolizing our money.

Becka,
The Calvary Chapels I have been to do it this way. No offering plate passed and a lock box outside the sanctuary.

requirement to tithe is under the Law again , which Christ already fulfilled for us so that we could just give as we will , cheerfully .
The Word : The Lord loves a cheerful giver !