The funds requirement for your subsistence in Germany will be around β¬4000, but you will also have to convince the visa official that you are going to leave the Schengen area afterwards.
The best way to do that is a stable, well-paid job. The pattern of income and expenditure matters, not just the amount of money when you make the application.
Another way are solid ties to the local economy and society at your place of residence. That can mean relatives who do not travel with you, or owning property.
Depending on his financial situation and residency status, your husband may be able to file a written bond with the municipal authorities where he promises to pay for any cost of overstay (unintentional or intentional). Such a VerpflichungserklΓ€rung is no guarantee of a visa, but it can help.
Instead of a tourist visa for 90 days, ask on Expatriates Stack Exchange about family reunification visa.