Where to buy wide glass vases?

I was just going to suggest the dollar tree or Walmart. Especially since V-day is coming up, you could wait for those go on sale, That's what I did for my anniversary decorations one year. If not I'd try Amazon.

Have you looked at IKEA? They have all kinds of vases

Do not buy glass online because it is heavy and expensive to shop. Plus extremely fragile. Dollar Tree is your best bet if you don’t want to go with what the florist rents out. If you rent, you don’t have to rehome anything which is stress and time. Otherwise in large cities, there are flower districts where flowers and supplies are sold at wholesale prices to the public. They are very inexpensive if they are local to you but again you have to rehome them which not everyone wants or has time to do.

Check out the Dollar Tree website too, you can have everything shipped to the store for free shipping. I'm getting a huge chunk of my candle holders from them - I needed a large amount (as each table is getting multiple and I have a lot of tables) and I ended up finding some great ones on their website. I'm just waiting for them to show up so I can add them to my stash of wedding supplies in our garage.

My other suggestion would be to check out wholesale party supply places (such as orientaltrading.com or efavormart.com) depending on how many you need. Amazon is also a great resource, though you may have to do some creative wording to find what you want. I needed lanterns for my centerpieces and I ended up finding them on Amazon for the cheapest around (especially because I needed 18 of them!).

Honestly do a google search for exactly what you want (5 inch vase bulk) and then go to the shopping tab. You'd be surprised what you can find there!