CMSM on FaceBook :: https://www.facebook.com/CentralMissouriScaleModelers
CMSM on Twitter :: https://twitter.com/CMSM_IPMS
CMSM on YouTube :: https://www.youtube.com/user/CMSMIPMS
Wikipedia "List of Scale Model Sizes and Common Use" :: https://en.wikipedia.org/wiki/List_of_scale_model_sizes
Sprue Brothers Models, LLC :: https://spruebrothers.com/
Also :: https://www.facebook.com/spruebrothers
Right here in Missouri and online. From their large facility in Liberty, Missouri, USA, they have everything a modeler needs from kits to paint to photo-etch.
Mark Twain Hobby Center :: https://www.facebook.com/MarkTwainHobbyCenter/
Also :: https://www.hobby1.com/
From St.Charles, Missouri, USA, online and storefront, with awesome customer service and delivery.
Samson R/C Hobby Shop :: https://www.facebook.com/SamsonRCHobbyShop
From Marshall, Missouri, USA, storefront and FaceBook. They have model kits as well as slot car, radio controlled vehicles, and doll house kits. Although they do not have an online store, they do accept phone/email orders and PayPal.
Factory Direct Models LLC - Factory Direct Models supplies custom-made military and civilian aircraft models to the world’s leading aerospace companies in more than 68 countries. Cool to see how the pros who build models for a living do it!
IPMS Gateway Club - St.Louis MO
Valhalla's Gate on FaceBook - Modelling supplies and paint
A Guide to Building Model Aircraft -- (Recommended by Lake Jennings BSA Troop 325)
Amati Ship Models, USA -- Sailing and historical ships
BlueJacket Ship Crafters -- Sailing ship, sailboats, modern warships
Armorama -- Armor kit reviews, new kit/product reviews, discussion forums
AeroScale -- Airplanes
AutoModeler -- Cars and automobiles
HFModeling -- Figures, animals, and creatures
ModelShipwrights -- Ships and boats
A Guide to Building Your First Ship in a Bottle -- (Recommended by Abigail, Erik, and ? Lynwood)
6thScale -- 1/6th Scale (large scale) Modeling
RailRoad Modeling -- scale model railroad models
ModelGeek -- General Modelling and especially Science Fiction
FlagShip Models -- USA Civil War model kits
Revell Online -- 'nuff said.
Model RoundUp -- Every car kit ever made
Micro-Mark -- who'da thought they'd have model kits?
CyberModeler -- Kit reviews, reference material including photos of the 1:1 item
Perth Military Modelling -- Some kit reviews, submitted model pictures, some references
Voyager Model -- PE and resin detail enhancement sets for model kits
Verlinden -- PE detail enhancement sets, diorama starters, figures and accessories
Tamiya USA -- Their USA-based online store (if you can find your way past the radio-control stuff)
DragonModelsUSA -- Their USA-based online store