Small regular investments in the stock market today could help to boost your retirement income. : The State Pension offers an income of just £168.60 per week. If you’re worried about how you’ll survive on this amount when you retire, then it’s time to start investing. On Saturday, I explained how investing just £4 per week into the stock market could give you a £10k lump sum in 20 years. As promised, today I’m going to look at how you can start investing with as little as £25 per month.