@wildlemon0968
If you're talking about the regular apex packs, the drop rate is 7.4% (Which is about one legendary every 13.5 packs). So, statistically, you should get it within the next few packs. If not though, You at the very least are guaranteed a Legendary every 30th pack.
*EdIt*
Also, if you are looking for a specific legendary item, I advise you don't buy packs. It can be pretty easy to burn a lot of money chasing a specific item. If you really want something, either craft it with materials, or buy it ala carte from the store or something.
Now, if you're like me and are just hoping to build your collection of items, I don't think the packs themselves are all too bad. I'm never chasing specific items, just trying to unlock stuff. But, still, with any microtransactions that are based on RNG (You don't know what you're getting until you open it), Id advise caution and restraint. There's nothing wrong with spending some money on a game you enjoy, but it can be easy for to get yourself in too deep.
Just, be careful 🙂