I do not recommend Wedding Boutiques for shoes. These are specialist Wedding retailers and will stock a selection of shoes to compliment the Wedding dresses that they have in stock. If you purchase your shoes for the Happiest Day of your life from the same boutique that you have bought your dress from they will often not be sold as a matching set and will be overpriced. You could often find something comparable on the High Street or even available online but if you do opt to purchase online make sure you order from a retailer with a good returns policy and that you have adequate time for a different option if they are unsuitable or even worse never arrive.
Consider making your own shoes. Buy a plain pair of shoes in a suitable style and decorate them yourself. There is always plenty of tips and advice available online You can buy decorations such as beads, imitation pearls, etc from specialist craft stores and with a little imagination and some handiwork you can make the shoes that you want at a fraction of the cost of a designer pair.
Have you considered an alternative to what are considered traditional Wedding shoes? A long dress with a trail will often mean your shoes are obscured from view anyway so in theory if you felt comfortable you could wear almost any choice of shoe beneath your dress. There are many shoes such as ballet flats and court shoes that would be perfect to wear to get married although they are not considered specifically as Wedding shoes.
Try to shop clever and look for sales on the High Street where you may be able to pick up a real bargain. End of line and out of season shoes may be available very cheaply if you have an eye for a bargain. Large Department stores often have sales of footwear that will be appropriate for wearing with a Wedding dress. eBay is also worth looking at as many stores also have eBay shops that are discounted.
A final option to consider for cheap and affordable wedding shoes is to look for a used pair because after all they will still be relatively unused but often such shoes have sentimental value and although they have no real practical application as everyday wear, many women will want to keep their shoes as keepsakes just as they will treasure the dress they wore for matrimony.