You can simply use the in-built random range;
ã€€ã€€ã€€ã€€create [object] at (player.X+random(100,1000)[/code:24ihvrve]
This will create an object at least 100 to the right of the player, and at most 1000.
Alternatively, for both directions (of course, it's the same for the Y coordinate):
ã€€ã€€ã€€ã€€create [object] at (player.X+choose(random(100,1000), random(-1000,-100)[/code:24ihvrve]
The choose() function has no bias, so the two other random functions will have the same chance of happening.
Edit: details on choose() and random() here: [url=https://www.scirra.com/manual/126/system-expressions]https://www.scirra.com/manual/126/system-expressions[/url]