Some of the prices charged for a few bits of wood nailed together or a bit of Polypropylene or a stitched bag, (probably all bought in container loads from the Far East) are unbelievable.
I once needed a lot of boxes for lighting equipment, and when I tallied up the total cost it ran into £100's - nearly as much as the lighting itself, or even more in some cases!

. I bought a load of plywood from a privately owned local joinery / building trade supplier, and engaged the services of a local handyman to custom build them for me. A days' labour got me around 10 - 12 boxes, all nicely custom made to my requirements, along with little section compartments for G-Clamps, IEC and DMX leads and spare bulbs, and even with the material costs, it was around half of the cost of 'professional' boxes!. I foam lined and painted them myself to save further labour costs. Its amazing what you can save when you put your mind to it.
That idea is only cost effective if you have several boxes to make, but its worth considering as a one-off if you have several lighting effects all residing in their cardboard packing boxes! and want to get them cased but are put off by the thought of 8 x £58's!
However for one-off or new equipment casing requirements there exists some other options...
A tip I learned from another member of the forum some years ago, was to seek out and buy Ex Military Ammo cases, which make excellent sturdy flightcases for our line of work. They are available in both conventional wooden box and metal case styles, and with the addition of some black hammerite and internal / lid lining with adhesive backed foam, they make an excellent and very presentable lighting flightcase if you can find one of the right size and height. By definition they are also 'mil spec' and so built to last forever, and as a bonus they are often dust / splash proof as well and won't object to having heavier equipment stacked onto them.
Many sizes are available depending on stock and the outlet.
You can pick these up online or at various Army & Navy / Military surplus stores for around £5 to £15 depending on size. Buy several and negotiate a discount!.

As an alternative, these are also 'really useful boxes', which serve the same purpose. Often being big enough to fit two smaller moonflower effects in one box with some foam and a bit of thought.
http://www.reallyusefulproducts.co.uk/uk/html/boxdetails.php
Prices for the above 'achive' boxes vary, so its worth shopping around. They are often listed on Ebay and at most Stationary outlets as well as Viking Direct etc. Various colours are available and they are very sturdy.
I got two fairly large DMX scanners nicely into one of the larger boxes. Cost of the box was about £19, compared to 2x £60 each from the manufacturer

- the 45 litre version also fits most Datamoon style moonflowers.