So let's break-down these requirements
1. gives out quests depending on your level
if (BaseLevel < 80) {
mes "You are less than level 80";
//put quest stuff here
}
else if (BaseLevel <= 99) {
mes "You are less than or equal to level 99";
//put quest stuff here
}
else {
mes "You are more than level 99";
//put quest stuff here
}
close
2. quests would be one-shots
if (CharHasTakenThisQuest == 1) {
mes "You have already taken this quest";
close;
}
3. would have a unique text for the first time you speak
if (CharHasAlreadyTalkedToMe == 0) {
mes "Hey! This is the first time we've talked!";
set CharHasAlreadyTalkedToMe, 1;
}
Putting these together would look something like
prontera,150,150,5 script ThisSampleNPC 63,{
if (CharHasAlreadyTalkedToMe == 0) {
mes "Hey! This is the first time we've talked!";
set CharHasAlreadyTalkedToMe, 1;
}
if (CharHasTakenThisQuest == 1) {
mes "You have already taken this quest";
close;
}
if (CharQuestIsInProgress == 1) {
//validation of quest
}
if (BaseLevel < 80) {
mes "You are less than level 80";
//put quest stuff here
}
else if (BaseLevel <= 99) {
mes "You are less than or equal to level 99";
//put quest stuff here
}
else {
mes "You are more than level 99";
//put quest stuff here
}
close;
}
This may not be as clean but more or less it'll look like this.
I'll leave the creation and validation of quests to you