I used to work in the industry my tips would be :
Set a budget and work back from that and don't let vendors sway you from it.
Decide what really is important to you and what isn't. Eg The only flowers I was fussed about were the bouquet for me, buttonhole for groom and wee posies for the few bridesmaids I had, I didn't have table decorations or anything - honestly once the tables are laid even with simple tablecloths and silverware and glasses and the guests in their finery that's honestly enough to "decorate" the room I didn't even dress the chairs they really can't be seen once everyone is seated/milling about anyway
Do as much as you can yourself or allow others to do for you as a wedding gift. I did my own stationery aside from the order of service and the favours which I did just mints in either net for the ladies or wee boxes for the men. They're really not essential. One friend did the cake which was v generous of them and another did the flower girls dresses (I paid for the fabric)
I've also done stationery for others (calligraphy is a hobby of mine)
Photographer similar to a pp was just starting to do weddings but was an experienced photographer in another sphere and did a fab job.
It was a catered buffet and we bought in the booze ourselves (admittedly this was when you could still do a duty free booze cruise is how we did it)
Venue was church and then a sort of village hall deal we only paid for cleaners after and DJ but these days I agree you could set up your own playlist as long as you've a decent music player/speakers.
This time of year (just before Easter) is actually the best time to shop as vendors are clearing the decks of last years stock to make space for the new stock, this especially applies to bridal wear. Don't be averse to wearing ex display stock and bear in mind that a good bridal seamstress can work wonders. They can change the neckline, sleeves, straps, add or remove train etc mine was ex display stock.
This was almost 30 years ago but 120 guests for around £3k which even allowing for inflation would be around £6k now
And if you wanted you could do it even simpler and cheaper. I've helped with jeans and registry office type weddings costing less than £500 even with dinner for 6 after (bride and groom both sets of parents)