WWII
Putting together a decent "army" for any period can cost the proverbial arm-and-a-leg. Personally, I like to keep all my proverbial limbs...
So, what to do? You can chose a period/theme and shop around for cheap figures or even use paper figures, or you find the figures first and let them decide the choice of theme!
Shopping around, I picked up various boxes of 1/72nd scale WWII figures for EUR 7,50 a box. These were British 8th Army and German Africa Corp from Revell. A bit later, I came across some Airfix figures, again 8th Army and this time German infantry for EUR 3,00. Since early in the desert war, the Germans wore European style uniforms, but in a different colour, I figured they would do. There is a noticeable size difference between some of the Revell and Airfix figures, but since I'll be gaming solo, I don't really care.
Next up, a source of vehicles. Plastic model kits cost from about seven Euros and up. But to be honest, I've sort of lost my touch with plastic model kits, and the few I have lie not even half built in their boxes...
So, what to do. While searching the net for reference pictures, I came across quite a few web sites that do paper models. Several of these do WWII vehicles. Some are quite complex, while other are very simple. A site that has models that are a good compromise between ease of build and detail is Paper Tiger Armaments.
Tanks
I am slowly putting together some AFV models. From Paper Tiger Armaments, I bought the M3 Stuart, A13 Cruiser and Bren Carrier & 6 pounder ATG for the British and Empire forces and for the Germans, I got the PzKpfw II and PzKpfw III. These have set the theme for early North Africa, around 1940 to 1941, pre-8th Army.
Figures
I have aload of Airfix and Revell 1/72 scale figures in various stages of being painted. But since moving house, these are still stuffed away in a box somewhere... For quicker results, I have been looking at paper figures. Paper Tiger Armaments do not currently do figures in desert gear, so I probably go over to Junior General for these. I have already got a load of figures for some fantasy gaming printed up and mounted.