I would suggest doing a direct smear, or wet mount, if you are not trying to quantify the abundance of a parasite species, and are just looking for the range of helminths present.

Although Formol-ether is a good technique, I wouldn't recommend it as a fast, cheap or field-friendly option, although this depends a lot on what you consider a low-cost budget. There are other versions which allow you to use less dangerous chemicals (for example formol-tween combinations) and so the use of a laboratory with a fume cupboard is less necessary. But this technique requires an electric centrifuge, and you'd need to buy chemicals.

My main suggestion would be to consider floatations using either a salt solution, or a sugar solution. Cheap and easy to make, and quick to do. You also get a to see prevalence and abundance of parasites. It's fast, cheap, and relatively reliable, although do be aware that not all helminth eggs are light enough to float up and I don't have any specific advice about samples from the tropics - so that might be worth looking into. If you are wanting to store the samples rather than look at them straight away, then they can also be stored in a small amount of formalin before processing.

I hope those suggestions can be of use.

Based on Eggs per gram methods its possible to quantify the male worms only. The male worms also are equally pathogenic and there is no way of quantifying them. Yes wet direct smear gives indication of infection, this will be a useful method suitable for rural areas where a microscope and glass slides are expected to be available health centers. Dr Ramchandra V Pusulury

Kato-katz is very good method for the identification of helminthic eggs, and you can also use the willis method to concentrate the eggs and it is very cheap

Kato-Katz is very useful in the diagnosis as well as to monitor the treatment efficacy. As it is a concentration technique, it has better sensitivity than a direct smear. You can perform the Kato-Katz as well as other concentration technique such as ether-formaldehyde.

More over of our respect colleagues suggestions, I would like to suggest you a simple screening method. Mix about a Pease of each 5 or 10 samples of stools, do Kato-Katz or formalin - ether method on it. If find it positive then check all of 10 samples one by one. It may save some your time and charges.

Why don't you just do a simple zinc sulphate flotation?

I would also recomend to perform Baermann technique. Floatation methods are not useful to detect Stongyloides larvae in stool samples, and this is a parasite usually underdiagnosed in tropical areas.