Depends what type of budget you have. As your starting out am guessing its a small budget. Are you freelance or work in a salon?
I just started to do freelance this year and am looking at specialising in bridal makeup.
I've found the Urban Decay Naked Palettes (Especially 1 and 3) are brilliant for Bridal Eye Makeup. I love Sidecar and Buck in 1 for bridal makeup and I find Naked 3 really nice for Mother of the Bride.
Foundation wise you want something that isn't going to flashback in photographs and looks natural. I really like and i've seen loads of youtubers and other Makeup Artist's use MAC Face & Body, it doesn't flashback its light but buildable and also waterproof and gives a lovely healthy glow to the skin. I also have Estee Lauder Double Wear Light for someone who wants a more heavy/matte finish. Just buy the a dark and light shade and that way you can mix them together to create the perfect shade for your client.
Try and get a pro-card for most places like MAC, you get 35% discount and it makes a huge difference. For highlighter for wedding's I use MAC Cream Colour Base in Pearl or Hush. It gives a glow/sheen rather than looking glittery and I feel sometimes powder highlighters can look a little heavy/glittery on camera especially in daylight. The cream is just a bit more subtle. Or you could go for the Bobbi Brown Shimmer Brick I like Rose Quartz.
Blush wise, pinks and peaches are your friend, I have a couple MAC ones but if your on a budget Sleek do a palette of 3 blushes and they very pigmented.
A good nude lipliner, can't go wrong with the No7 Lipliner in Nude, Lisa Eldridge always uses it. I get it when they have the £3 off Makeup voucher. A couple nice nude lipsticks as well, I have Angel, Velvet Teddy and Ruby Woo (for a more vintage bridal look). Loads of drugstore brands have great nudes like revlon and rimmel.
A good setting powder will go along way as well, I prefer using the Chanel Loose Powder but its quite expensive but you get a huge amount and it makes the skin look amazing.
If your wanting to just get a kit from somewhere then i'd suggest MAC but try get the discount first. I wouldn't suggest buying things 2nd hand because you don't know how old the items are (could have gone off) and also if they are real (alot of the counterfit copies have dangerous ingredients in them). Its just not worth it when your dealing with clients. I knew a girl who bought some fake MAC products and used them on a customer and they had a huge allergic reaction and tried to sue her.