The cost of taking out a standard loan for between £7,500 and £15,000 dropped to the cheapest ever today, after Marks & Spencer slashed its loan rate to 3.3% rep APR.

The new rate, which is open to new M&S customers and those who already have an M&S financial product until 28 February 2016, undercuts the next best from Sainsbury's Bank, which is 3.4% rep APR for Nectar cardholders (otherwise 3.5%).

However, though borrowing is cheap when it's done right, don't use that as an invitation to do it. Only use it for planned spending – eg, a new car or kitchen – and for as little as you need. Aim to repay it as quickly as possible, making sure you've budgeted and checked repayments are affordable. For more see the Cheap Loans guide.

Who can get the M&S loan and what you need to know

New M&S customers and those who already have an M&S financial product (ie, an M&S credit card, bank account or loan) are eligible. You can apply online* or by phone.

Remember though, all loans are now 'representative' rate, which means only 51% of those accepted need to be given that rate, and the rest could pay more. The only way to know is to apply, and that marks your credit file.

Our Loans Eligibility Calculator (it performs a 'soft-search' that lenders can't see) can't tell you if you'll get the rate, but shows acceptance odds – the higher they are, anecdotally, the more likely you'll get the advertised rate.

All applicants require a credit check – see our Boost Your Credit Score guide. And if you're struggling with debt, see Debt Help.

Nationwide customer? You could get a 2.8% rep APR loan

If you're a current account holder with Nationwide, or you successfully apply for a current account with the bank, it promises to undercut the best loan offer you can get by 0.5 percentage points, meaning the best-buy 3.3% rep APR loan could become 2.8%.

To get the deal, you must first apply and get accepted for a loan through any bank or building society (including Hitachi, but not including peer-to-peer lenders such as Zopa).

Then, apply for a Nationwide loan – but you'll need proof of acceptance for the other loan. If Nationwide accepts you, it will then offer you a rate which is 0.5 percentage points lower than your initial offer (it says it won't accept you for the loan, then offer a higher rate). For full details, see Nationwide Loans Trick.

Best-buy loans for other amounts

Warning: Applying marks your credit file, so first find which loans you're most likely to be accepted for using our Loans Eligibility Calculator so you can minimise applications.

- For £5,000 – £7,499: M&S* and Zopa* offer 4.5% rep APR over one to five years.
- For £2,500 – £4,999: Hitachi* is 7.4% rep APR over two to five years. Peer-to-peer lenders Zopa* and Ratesetter* have personalised rates and may undercut it. Full info: Cheap Loans (APR examples).

For smaller amounts, 0% credit card loans win

A few specialist cards allow money transfers, where the card pays cash into your bank account like a loan, then you owe it instead. Accepted new Virgin* (Eligibility Calc) cardholders can get 32 months 0% for just a 1.69% one-off fee (min £3).

Just never miss a min repayment and clear before the 0% ends or it's 20.9% rep APR. Full step-by-step help and more best buys in Money Transfers.