If your car insurance premium is large and verging on impossible to pay at once at the start of the policy then it is worthwhile looking for a policy that will let you pay monthly.
Monthly car insurance usually involves paying a one off deposit and then repaying the balance each month by direct debit. Insurers often run special offers which mean you get two free months or more of insurance cover for free, this may make the policy more affordable. Most insurance policies that are taken out monthly are paid for by a credit firm and you will be responsible for paying your insurance through that company rather than to the insurance firm direct.
If you shop around and use insurance price comparison websites you will probably find several insurers also offer you the opportunity to pay no deposit whatsoever and go straight to the monthly payments which will be slightly higher. In this case it is all about what you can afford personally and your other monthly outgoings.
It is also important to note that unless otherwise specifically stated your monthly repayments will also be charged interest at a rate which could be up to 20% or even more, this increases the total cost of your insurance premium and when shopping around you should make sure you are comparing the total costs of paying monthly (deposit, monthly payments and interest rates) rather than the cost of paying the insurance premium up front as this often works out significantly cheaper.
If you add another person or car to your policy which increases your insurance premium then any additional cost will be spread across your monthly repayments, if this occurs near the end of the policy you may be asked to pay upfront, this increase in cost is something you will need to consider.
The various insurers will all have different ways they expect you to pay your monthly fees, although the most popular is by direct debit they may request a standing order, credit card or other means. You should also read your policy terms and conditions carefully to see if you would be charged any additional costs if you accidentally default on one of your monthly payments or pay late. You will of course also any standard bank charges.
Any administration costs you incur during your policy will be also deducted, usually though the same direct debit and once again you should look into these carefully before purchasing your policy.