what can I tell my friends when they offer me narcotics?

Tell them nothing. CHANGE THESE PEOPLE. They are not friends. A "friend" you could call at 2AM in the rain and tell them you have 2 flat tires and need help. A friend would help. l guess these friends may help you. Especially if they are so high (or low on narcotics) that they don't feel the cold rain.

Just normally tell them NO

If you are a fan of the late Nancy Reagan, (who was famous for giving some of the most enthusiastic blow-jobs in Hollywood),  you can  Just Say No.   You will then be awarded the Mr T medal for pharmaceutical purity and will win a guided tour of Sesame Street.    Or you could say yes and get nicely off your head..

Whatever you want to .

'No thanks' is probably a good idea. 

i would just tell them no

Tell them you are thankful for the free drugs then go sell them and make a gross profit.

"Just Say No"               .

I don't need any right now.

Who's paying for this?

I don't have any money.