where is a cheap place to buy these bulbs ??

You can check out suppliers on the RHS website
www.rhs.org.uk.
Click on the 'Plants' tab, and use Plant Finder. There are 36 suppliers including many who offer mail order

25 bulbs £3.95 from Dobies although you may get them cheaper~try Avon bulbs Somerset

Acidanthera murielae is now called Gladiolus calianthus just to confuse matters.

I bought 10 bulbs for £1 off ebay last year, also jparkers have had some good deals on them - just type jparker into google and it will come up. - wrong time of year to plant them though, so might be best to wait a few months and you will find them much easier to get hold of.

I bought 50 bulbs of acidanthera murieliae, aka peacock orchids, for £1 at Poundland in Carlisle today. They seem plump and healthy, and I was trawling around to see the best way to grow them. Unfortunately, most of the websites are American, and weather there is very diverse; I live in Cumbria. Will try them in different places outside, and the weather isn't that inclement up here, and some indoors. Any tips on growing would be gratefully received.

Yep, I too got a packet of these as an impulse buy from Poundland whan I was looking for slug pellets. As they seem tbe related to gladioli I'm going to treat them similarly. I'm down by the solent so the weather isn't a problem usually.
Planting them today and when they come up and when they flower, I'll post some pics.

As an obiter, I have to thank my peacock orchids for finding this excellent website; but shame about the American spelling, and the wiggly lines questioning my almost perfect English! Planted my bulbs, which as Gardendenny rightly says are related to gladioli (found that online!), in pots in the from north to east facing front garden and also in the south to west facing back garden. They are coming up strongly in the pots in the front, but I have had to insert BBQ skewers in the ground where those in the back are planted under the lovely Autumnalis tree, to give them a chance to survive as my cat likes to sit there. Didn't plant any in pots for indoors.