Personally I wouldn't spend money on presets. You would be better off learning how to make your own depending on your workflow
Pretty much this. For presets to be effective they generally require that you start with an image that already has a certain overall exposure and look designed to be used with that preset. This generally requires you putting in some time up front with the image to get it that way,
then save a copy on which you would apply the preset. Why? Because presets are not relative to your starting point, they are absolutes. So if you needed to apply exposure and white balance adjustments to get to that starting point they will be wiped out after you apply the preset. IN other words the only way to make them work effectively is to perfectly expose the shot SOOC every time. Otherwise you go 1) apply preset, 2) fix preset, which really isn't a time saver.
The only ones that
might be worth paying for are some of the ones that give you a different film look, but even with these I'd never use them in Lightroom, I would apply them using the Camera Raw filter in Photoshop since it can be added as a layer to an already adjusted image and saved with that (Camera Raw is identical to the Lightroom Develop module).