Post office Monthly income scheme: Invest in Post Office Small Savings Schemes for guaranteed income. Under this scheme of the government, husband and wife can open a joint account. There is guaranteed income every month after lump sum investment in this. The government has doubled its limit in Budget 2023 itself. You can earn with the help of Post Office Monthly Income Scheme. Both single and joint (up to 3 persons) accounts can be opened in the scheme. Its maturity is 5 years. Currently, 7.4 percent interest is being given on MIS from April 1, 2023.