THE BEST WAY TO CALL HOME IS TO BUY A THAI SIM CARD (VERY CHEAP ABOUT 200 BT)
for 7 Baht per min though the "009" access. For the UK, key 009-44-area code (less the leading "0") and the number.
Anyone can buy a mobile over here. There are hundreds of Mobile Phone shops all over town. Simple phones start from under 2,000 Baht or maybe your own phone will take the SIM card.
In Thailand, new mobile are sold UNLOCKED, so you can take them home and use your own SIM card in it. The language will include English by maybe not your home language.
You can buy top-up cards at shops and 711 stores. Most will enter the code for you. This buys you line rental period and call cost value. If you use it a lot, when putting in call value, you may well give it enough rental credit to keep the number live until your next visit.
Internet cafes: They offer VoIP calls from their PCs.
Kerbside Stalls: They use mobiles and charge a few Baht extra, but saves you buying a mobile here.