Question needs more information. Which country and which operator
yes
Buy Roaming sim cards.
Yes
1p
check with your carrier. often it is quite expensive.
Yes, a US SIM card will work in Canada, but roaming charges may apply.
Purchasing a SIM card from 02 is not difficult. The SIM card can be pay and go, and allows savings on roaming charges. SIM cards can be purchased at mobile stores.
it cost 25 cents each text message
5-10 usd
Depends what country you are in.
Mobile phones will automatically activate the roaming feature if necessary. Roaming time used is chargeable above the contracted monthly rates. There is no reason to manually activate roaming.
Yes, as long as you have a SIM Card to swap in to avoid roaming charges.