Self-Invested Personal Pensions (Sipps) allow you to manage your own retirement pot rather than leaving it to fund managers. The Financial Services Authority has warned that some people have been given the hard sell on Sipps when a more simple stakeholder or personal pension plan would be more suitable. You should only opt for a Sipp if you are comfortable making your own investment decisions.

A Sipp can be used to hold a wide range of investments from shares, gilts, unit trusts, investment trusts, insurance company funds and commercial property (but not private property). You also have more choice if the investments perform badly - you can simply move the money to another investment house, rather than being tied when a fund performs badly. You can make the decisions yourself, or use a stockbroker or financial adviser to do it for you.

Questions to ask to find the cheapest SIPP

1. What is the set-up fee? It's typically anything from nothing to £500.

2. What is the Sipp annual management fee? This is a small percentage applied every year that will eat away at your returns. More commonly, it is a flat fee. You should aim to find a fee-free plan.

3. How much are annual fees on the funds? These are the ongoing charges applied to funds that you put into your Sipp, typically 1.5% a year. A decent provider should be able to minimise the cost.

4. How much are initial charges on funds - Oeics and unit trusts? These fees are typically 5% but a decent provider should be able to discount these to very little. Check the discounts on the actual funds you're planning to buy by using providers' websites.

5. How much are dealing charges on shares and investment trusts?

6. How much are the transfer fees? These are charges applied for moving money, funds or shares into a Sipp from another provider. Also, check if there any exit fees on moving to another pension provider.

7. What rate of interest will I get? Interest rates on cash left in a Sipp vary from 0.1% up to 4.5% (at least they did when the bank rate was much higher). If you expect to keep some of your pension in cash, check what the rate is. For example, Fidelity currently pays one basis point below the UK bank rate.

8. What are the other charges? Look out for the costs for buying an annuity, costs for paying out on death, etc. Remember that these one-off fees are less important than finding Sipps with cheap annual fees.