Another service offering advice on buying your pension annuity was launched this week, after Tesco said it would soon be offering pensions on its comparison website.

The price of the annuity you have to buy with your retirement pot has astonishingly risen by up to 30% since the financial crash.

However, should you really be buying your pension alongside your car or pet insurance?

A man who retired in 2009 would have needed a pension pot of £118,000 to buy an annual income of £5000 and for a woman it was £133,500. Now there are unisex rates and the cost has shot up to almost £153,000.

Yet as many as four retirees out of 10 still accept the offer they get from their pension company, and pay up to 40% too much by failing to shop around. No wonder new services are springing up, when financial advice has all but dis-appeared from the high street because it now has to be paid for by upfront fees, not hidden commissions.

This week's launch sees Payingtoomuch.com, run by Eclipse Financial Systems and endorsed by names such as Legal & General and LV=, offer information on enhanced annuities and a "find an adviser" service. It has a maximum commission charge on sales of 2.24%, potentially below the 1.5% to 3.5% charged by market giant Hargreaves Lansdown – which has attracted some criticism.

Pensions expert Dr Ros Altmann said: "Commission of 3.5% could cut the spending power of an average-sized £30,000 pot by just over £1000. - this is a high sum."

Tom McPhail, at Hargreaves, says many companies with lower commission rates were not matching its annuity terms, which were boosting clients' income by nearly 30%.

However, following Tesco's announcement of plans to expand its Tesco Compare service to include annuities, Nick Flynn, at independent advisers LEBC, said: "While it is very good news that many more people approaching retirement will be aware they have options, we are concerned that buying an annuity direct from the Tesco Compare website without seeking professional advice could lead to thousands of individuals regretting the decisions they make, because once taken they cannot be undone. Also, will the Tesco Compare service be whole of market?"

He adds: "There are other factors to be considered, such as providing for a spouse or partner, linking the income to inflation, entitlement to enhanced annuities because of ill health, guaranteeing payments for a fixed period.

"You may also find that the commissions being charged by the Tesco Compare service could cover the fee for obtaining professional independent advice."

In a new report sponsored by MGM Advantage and Prudential, retirement expert Billy Burrows argues that conventional annuity rates have sunk so low that people with above-average pension pots (£50,000 plus) should consider alternative products such as investment-linked annuities. He says their advantage is in "paying investors a relatively high starting income with the potential for future growth and flexibility".

However, for those with bigger pension pots, annuities are not the only option.

Patrick Connolly, certified financial planner at AWD Chase de Vere, said: "Of even greater concern is those who go into income drawdown without advice. Before even thinking about the most appropriate drawdown product, there are a host of suitability considerations which must be addressed, including the size of the pension fund, other sources of retirement income and investment assets, the risk profile and age of the investor, and an analysis of drawdown versus annuity."

Meanwhile, for those already in drawdown, another adviser has warned that many retirees may be drawing down more money from their pension than they can afford, following a recent change in government rules.

Some pension companies have automatically increased the amount of income they pay out to drawdown pensioners in response to a 20% uplift in the maximum amount permitted, known as 120% of GAD (Government Actuary's Department) rather than 100%.

But David Trenner, at Glasgow-based Intelligent Pensions, said: "It would be more prudent for providers to request action be taken for an increase in income rather than the other way around."

John Fox, managing director of Liberty SIPP, said its calculations showed that taking the higher GAD rate would boost income by 12% a year in the first 10 years of retirement, but reduce it by 7% in the second decade – and by 41% for those living into a third decade. He said: "The extra income people take now has to come from somewhere and that somewhere is the future income of the fund. For some, short-term gain could well result in long-term pain."