NHBS has a good on-line equipment shop. They are not cheap but their delivery system works well. see: https://www.nhbs.com/equipment

https://www.scientificlabs.co.uk/

https://www.labexchange.com/en.html

https://www.edulab.com/

https://entomopraxis.com/tienda/es/22-macroinvertebrados-y-plancton-acuaticos-seccion-tematica

https://www.weboryx.com/oryx/equipo/EV08

Hi Raquel:

BioQuip is a good resource for insect related:

https://www.bioquip.com/

Also try WildCo for nets and grab samplers:

https://wildco.com/sampling-resources/

https://shop.sciencefirst.com/wildco/

Acorn Naturalists is geared toward nature education products but also have a variety of sampling nets and other gear:

https://www.acornnaturalists.com/products/field-equipment-supplies.html?cat=1820

I hope this helps!

Thanks! Relly good ones!