under construction - please vote accordingly ;)
1> There are a number of ways of saving money on your warhammer hobby and heres a few ideas
GamesWorkshop paints are great for high detail painting but for undercoats on vehicles or painting large areas such as walls or roads you may want to think about ordinary artists acrylic or even vinyl wall paint. Black with grey drybrush can cover a battleboard full of buildings and it will cost a fraction of what GW little pots or even spray paint costs likewise green acrylic with some scater thrown over it will do for most bases.
As for trees, foliage and even some buildings - try secondhand model railway stuff. It usually works out cheaper than even secondhand warhammer scenery but watch out for the buildings as they are slightly smaller scale (chimneys, bridges and gas storage buildings still look good with warhammer though).
The warhammer buildings GW have pumped out over the last couple of years have been a godsend to gamers but look silly if you have a big gameboard with only a couple of buildings stuck in the middle. So lets talk foamboard - foam with cardboard sandwiched either side, which you can buy from artists shops. You can make fairly reasonable buildings out of it even if you don't have any GW spare bits to stick on but if you do buy GW buildings you can make them go further by making 1 blank wall out of foamboard and using half the GW bits for the other wall. Do this again and hay presto - 1 building turns into 2 :)
Alternativly - you can buy cities of death and other parts of buildings from Ebay shops and stick small numbers of parts to foamcard to simulate ruins - it might work out cheaper than buying whole buildings but you have to shop around.
As for filler, instead of using greenstuff on vehicles and scenery, think about using no-more-nails... Its a hell of a lot cheaper for filling large areas and it can be proded and sanded to look like rocks / stone.
For models, it is possible to cut corners but with mixed results. Prince August 32mm elf moulds let you cast reasonable looking elf bodies - a few GW elf or dark elf arms/ heads/weapons and a paint job = you will hardly notice the differance. Likewise, i think airfix robogear looks similar to imperial guard models - do the head and weapon trick and hay presto :) The downside to this is that they are slightly taller and 1= you can't sell them as warhammer when your bored and 2= you won't be able to use them in shop based tournaments. Also, metal and plastic or polysterene plastic and non-poly don't stick together very well so you will have to pin things together as well if you want them to stay in one piece.
Finally, think about using an older set of rules. In the earlier versions you could have allies so if you buy a secondhand collection with oddments of different races but not enough for a full army of one particular type you could scrape together say an empire army with dwarf and elf allies if you find the right rulebook.
BATTLEBOARDS / SCENERY
Collecting the models is only half the fun, a boring battleboard makes a boring game. As a rule of thumb I have at least a quarter of the board with scenery on it. Always leave a hands width between scenery items so you can move the models around and the more levels the board has - the more interesting it is.
Having a mixture of 1,2,3 and even 4 story buildings to run around is a good start - think mordheim or necromunda style. Also, if you use tiered hills and spread buildings over different levels it adds even more variety. If you very adventurious you could even cut sections out of the board and include cellars / sewers for your soldiers to fight over. A side effect of having more terrain to run around is that games will take longer so you could tecnically get away with using fewer soldiers (cheaper) and the game will last the same length of time.
If you have the money and you wan't to make a battleboard / game to drool over you could try using some 1980s / early 1990s warhammer and dungeons and dragons bits. There was a lot more variety and sense of humour back in the day - you don't see GW making models of a dwarf having a poo while reading a newspaper thesedays do you? There were all sorts of things to add details to your scenery including traps, wizards furniture, tavern furniture, bookcases, toilets, treasure, naked women :), torture equipment and market goods. Yummey :) - one thing i notice when i look at white dwarf and the games they play is the lack of everyday life items in the scenery like farm animals and food so thats something i add to my scenery.
I'm no pro-painter but i have learned how to make my models look reasonably decent...
1> Helmets are your friend, painting faces is a pain in the butt especially human skin tones so if it comes with a helmet option and your new to painting - use them.
2> A lot of models have weapons/appendages which overlap each other or the main body so before you glue together look at how the model will look when assembled and paint some of the parts before glueing together.
3> Think about using a short-hair nylon brush for detail work - long haired sable brushes tend to fan-out after a while which makes detailed painting more difficult.