If you are putting your bulbs in pots multipurpose compost is the cheapest option and you need not add any grit. If you need grit try your local farm shop or bird food supplier.

Isn't it simply sand? That's what I've used to loosen up compacted soil - good for growing carrots and beets. "Horticultural Grit" sometimes has dyes & pigments added to make it look pretty. That's why it costs more. I can pick up a 60lb bag of all-purpose sand from The Home Depot for $5.40. It's 100% washed silica sand in its purest form. This can be added to compost.

our builders sand isn't really suitable in pots. it is certainly not washed. if you want to use a grittier compost use a soil based type like john innes.no 3. but to be honest I tend to use a general purpose compost mixed with my own soil. you could also add vermiculite as a layer to sit the bulbs on.
if the bulbs are for indoors [forced] then use bulb fibre.

You can usually buy grit from a builders merchant for eg harling walls, much cheaper. I use 6mm grit and always add it to the compost for bulbs.

Agree with Bulbaholic . . . buy from a builders merchant.

I'm looking myself and the best deal I can find is at Squires. RHS potting compost £4-99 each or 3 for £12. 20kg bags. I'm off in the morning to buy some.

One of the top bulb growers does not recommend adding grit to compost for bulbs. He reckons it scratches the bulbs and allows pathogens to get in. What he does suggest is sitting the bulbs on a layer of sharp sand and then covering with MPC.
I buy Sharp sand from our local Builders Merchant at a good price. It comes from inland sources, so no salt or sea shells in it.

Thank you all for your good advice. I will not be buying any horticultural grit but I will be visiting my local builders merchant to see what they sell and save some money! Hopefully I will have some lovely flowers next spring.

"Sharp sand"? That's what we are talking about. Sharp sand, grit, builders sand, silica. It's all the same thing, maybe slightly different grades. Double check on the "builders sand' to be sure it doesn't have unwanted additives or chemicals. I prefer to use pure sand without the dyes and additives. I agree with Bulbaholic on this one. Good idea to mix in some Grit, sand, silica, etc. Mix it into the compost for good drainage, aeration (gas exchange) & so the roots can easily penetrate and the bulbs can divide better in a loose fluffy compost.

Maybe in the USA, but here Builder's sand is used for making mortar as it 'clings' together. Again in the UK it is usually red in colour.
If it makes sandcastles it is no use for compost.

If you add sand you are adding siica. That's what sand mostly is. If you want coarse sand see if you can find Calais sand. Always used to use this in cactus compost but haven't seen any for years. If you get builders sharp sand make sure it doesn't come from the sea shore.

Sorry my comment should have read potting grit not compost. I bought it this morning in that torrential rain we had and going to give it a go tomorrow.

Owd - I know what 'builder's sand' is and you obviously did not read my comment.