It only makes the sound in the morning and every time it's turned on after that it doesn't. It sounds like the car is trying to turn over once or twice then comes to life. We went to orileys and they said the alternator wasn't giving the battery enough power. Replaced it but it still made the sound this morning? We also already know it's not the battery. What else could it be? Could it just be the change in weather?
If they changed the alternator without giving the battery a charge at the same time then it's possible that it is still in a relatively low state of charge (hence the slow cranking/starting).
Try taking the car out for a substantial drive (>45 mins) - you'll want some load on it rather than just idling. Then shut off and try re-starting - if the problem persists then you have another underlying issue but if it clears then you're all good.
If it doesn't clear
This would indicate that there is another issue causing the car to struggle to start - given the initial symptoms suggested the alternator it's most likely something electrical and a bad ground somewhere in the system preventing the alternator delivering correct charge to the battery would be the prime suspect.
You can get the battery health checked with a decent auto mechanic or a simple test with a multimeter across the terminals to see what the voltage is. It's not a complete indicator of battery starting health but insufficient voltage there would be a strong indicator of poor charging.
If the battery charge and health checks out but the problem persists then there's a different issue at work - hard to say for sure what that might be but either the starter motor itself or crankshaft position sensor would be possibilities.