Every bride wants invitations or stationery that is custom. Not everyone is comfortable with something store-bought. If that's you, but you'd like to keep costs low, then head over to three of the top online sites that allow you to get custom-designed wedding invitations that you can print yourself or have a commercial printer do for you.
Costs vary, but many of these options can be done for as little as $5. All you have to do is search for wedding invitations and dozens of designers (and their portfolios) will appear. Find a designer you like and then begin the process of ordering an invitation design. Once the particulars are figured out, and you've paid, all you have to do is take your pdf (e-document) to a print shop to have printed. To save even more money, you could simply print them yourself on nice card stock.
If you're looking for something bespoke or avant garde, Etsy should be your first go-to for custom invitations. Prices vary across the board. High and low, it all depends on what you are getting.
If, in your search you decide that you don't want to hassle with the printing portion, then you can choose a designer that will also take care of that too. Etsy has tons and tons of wedding invitation options.
Fiverr pioneered the idea that anyone could be hired to do almost anything for five bucks. Their easy to use platform and success rate have produced a lot of (now defunct) copycats.
As far as quantity, Fiverr has more available designers than any other platform. While the style and expertise vary from one to the next, it should be relatively easy to find a designer with a portfolio that you love.
Jobs start at $5 and go up from there. Typically, these jobs include 1-2 complimentary changes. Alterations, among other things, such as expedited e-delivery, will cost extra-typically in increments of $5.