Over the past few years, SIM-only contracts have seen something of a resurgence in the consumer market. There are at least two reasons for this. Firstly, carriers (or networks) don't make much money on selling phones, and so they can make practically pure profit from selling you a SIM-only contract.

Secondly, consumers have watched as regular contract tariffs monthly costs have grown from around £35 per month to almost £50 per month. SIM-only then, is much more affordable than a conventional phone+line contract.

SIM-only can often be the best way to get great value for money, especially if you already have a phone, or if you'd rather buy your unlocked phones direct from manufacturers.

Here, we will round up the best available SIM only deals available right now.

£14 a month for 12 months which includes 12GB data, unlimited minutes and unlimited texts. See this deal here.

£25 a month for 12 months which includes 100GB data, unlimited minutes and texts. You can use your Three mobile sim in over 60 countries. Three boast a 97% UK coverage. Read more about this offer here.

£17 a month for 12 months which includes 30GB data, unlimited minutes and texts. See this deal here.

£21 a month (offer ends on 3rd October) for 18GB data. EU roaming included in 48 countries. Read more about this offer here.

£26 a month for 12 months which includes 22GB data, unlimited texts and calls. You can use your data text and minutes in the EU without incurring further charges. You also get access to the BT Sport app for 3 months. Read more about this offer here.

BT currently have a sim only offer for £21 (£16 if you have BT broadband) a month which includes 12GB data (double data for a limited time), unlimited minutes and texts and unlimited BT Wi-Fi. There is also a promotion currently where you will get a £60 Amazon or iTunes gift card. Read more about this offer here.

BT also have a sim only offer for £20 a month (£25 if you don't have BT broadband) which includes 20GB data (an extra 5GB for a limited time) unlimited minutes and texts and unlimited BT Wi-Fi. You also get a £85 gift card for either iTunes or Amazon with this offer. Read more about it here.

Exclusive offer: 4GB data, unlimited texts and unlimited minutes for only £15 a month (£10 if you are a BT broadband customer). You also get a £50 iTunes or Amazon gift card with this offer. Read more about this deal here.

Limited time offer: 8GB data, unlimited texts and unlimited minutes for only £20 a  month (£15 if you are a BT broadband customer). You also get a £90 iTunes or Amazon gift card. See this deal here.

15GB data, unlimited minutes and unlimited tests is now only £20 on O2 (reduced from £35) saving you £15 per month over 12 months. You also get daily benefits with O2 priority and free O2 Wi-Fi. See this deal here.

Right now you can get 25GB with O2 and unlimited texts and minutes for only £25 (reduced from £40) saving you £15 per month over 12 months. This offer ends soon so be quick to take advantage of this offer. See this deal here.

£20 a month for 12 months which includes 20GB data, unlimited texts and calls. You have a choice of either Spotify Premium, NOWTV or Sky Sports mobile for 12 months. Vodafone global roaming in 110 countries is also included. You can also get a £25 Currys PC World Gift Card right now with this offer. Read more about this offer here.

£25 a month for 12 months which includes 25GB data, unlimited texts and calls. You also get the same benefits as the above deal. Read more about this deal here.

£25 a month for 12 month which includes 25GB data, 5000 minutes and unlimited texts. If you have Virgin Media broadband or TV, you'll also be able to get unlimited minutes to other Virgin mobiles. Read more about this offer here.

£9 a month for 12 months which includes 4GB data, unlimited texts and 1500 minutes. Read more about this offer here.

£12 a month for 12 months which includes 8GB data, unlimited texts and 2500 minutes. Read more about this offer here.

£12.50 a month for 12 months which includes 6GB data, 3000 minutes and 5000 texts. Tesco use the O2 network to run their service. Read more about this offer here.

£18.00 a month for 12 months which includes 12GB data, 5000 minutes and 5000 texts. Read more about this offer here.

£8 a month on a 30 day rolling contract, 3GB data, 1000 minutes, unlimited texts for £8 a month. Read more about this offer here.

£10 a month on a 30 day rolling contract which includes 2GB data, 1500 minutes and unlimited texts. PlusNet use the EE network so expect fast 4G speeds. Read more about this offer here.

£6.00 a month on a 30 day contract which includes 1.5GB data, 2000 minutes and 1000 texts. Read more about this offer here.

The People's Operator currently has a great offer for £3.99 a month for 1GB of 4G data, 500 minutes and unlimited texts. TPO use Three's network which has a 97% coverage of the UK. Read more about this deal here.

£10 a month with 5GB 4G data, 500 minutes, 5000 texts on a monthly rolling contract. You can use your ID Mobile sim in 50 countries and uses the Three network. Read more about this offer here

Below you'll find links to the four coverage checkers you need. Why four? Because any other network is an MVNO (Mobile Virtual Network Operator), which means they don't have their own masts and signal, they use the networks provided by Vodafone, EE or O2. GiffGaff and Tesco mobile, for instance, uses O2's network, while BT Mobile uses EE's.

Or, if you'd rather go independent, you can try Ofcom's mobile signal checker.