Here's a selection of Biology Supply companies to help with planning of comp budgets. Listing of companies does not imply an endorsement of their products.
ATCC. American Type Culture Collection. The most comprehensive source for bacterial, fungal, animal, viral and plant cell cultures. Before you order from here, you might check other sources -- sometimes you can obtain cultures for free from other researchers that would otherwise swallow a large part of your budget.
Ambion. Specializes in kits and supplies for RNA work of any kind.
BioRad. Often best prices on agarose; other gel running supplies.
Carolina Biological Supplies. Specialty seeds / living plant materials.
ChemService. Specialty chemicals. Best source for pesticide standards, auxin transport inhbitors.
Duchefa. Plant tissue culture media and supplies.
Fisher. Large selection of just about everything from lab equipment to chemicals and supplies. Some discounts may apply.
GibcoBRL. Biotechnology & tissue culture supplies.
LPS. Often has the best deals on plasticware
Molecular Probes. Specialty chemicals for microscopy and other optical applications.
NEB. Often has best prices for enzymes.
PhytoTechnology. Often competitive pricing for plant tissue culture supplies.
Promega. Molecular biology supplies.
Sigma. Large selection of chemicals - figure in high delivery costs when comparing prices with Fisher.