Is the church a business?
Generally a business is "an organization established for generating profit; a commercial organization." As such, the church is not a business.
It is an organization, established by God for the primary purpose of worshiping Him and spreading the good news of salvation to mankind.
The church holds assemblies. "And let us consider one another in order to stir up love and good works, not forsaking the assembling of ourselves together, as is the manner of some, but exhorting one another, and so much the more as you see the Day approaching" (Hebrews 10:24-25). At these assemblies, acts of worship are to be done, such as partaking of the Lord's Supper, prayer, giving, singing, and learning. (Acts 2:42; I Corinthians 11; I Corinthians 14).
The church exists to uphold and support the truth to the world. "I write so that you may know how you ought to conduct yourself in the house of God, which is the church of the living God, the pillar and ground of the truth" (I Timothy 3:15). A pillar is a pedestal used to display an item and "ground" refers to the foundation. The church doesn't originate doctrine. It is the means God uses to place His doctrine on display and the organization He uses to support His teachings. The church accomplishes this mission through teaching both its members and non-members. The church was created "to the intent that now the manifold wisdom of God might be made known by the church to the principalities and powers in the heavenly places, according to the eternal purpose which He accomplished in Christ Jesus our Lord" (Ephesians 3:10-11). "And He Himself gave some to be apostles, some prophets, some evangelists, and some pastors and teachers, for the equipping of the saints for the work of ministry, for the edifying of the body of Christ, till we all come to the unity of the faith and of the knowledge of the Son of God, to a perfect man, to the measure of the stature of the fullness of Christ" (Ephesians 4:11-13). As an example of reaching non-members, the church in Antioch sent out Paul and Barnabas to preach the gospel (Acts 13:1-3).
Where a business sells merchandise or services, the church's sole legitimate means of raising funds for operation is by means of voluntary contributions. "On the first day of the week let each one of you lay something aside, storing up as he may prosper" (I Corinthians 16:2). "So let each one give as he purposes in his heart, not grudgingly or of necessity; for God loves a cheerful giver" (II Corinthians 9:7).