There is a better solution or approach to collecting model trains. If you are just starting out, and you have not bought your first set than you are in a good position. The reason being that it is better to create your own set by purchasing each car separately. Now if you are out to be a train set collector than that is a different ball of wax, but to have say a Lionel trains set that fits your personality is golden wouldn't you agree.
If you want to build a layout, using HO or N scale will be of great benefit because of the great selection of model rail cars to choose from. Now the beginning of your collection would be the locomotive, I enjoy the variety that Lionel train engines have to offer. You should only purchase the best one you can afford no need for bells and whistles at this stage.
If you want to reduce what you spend your money on don't buy a lot of structures and as hard as it may be limit yourself to the number of rail cars you initially buy. Used Lionel trains can be found at great prices just know what you are looking for before you purchase. Its a good idea to buy extra sections of track for a starter track layout. You'll want enough flex track to build maybe an oval, some turnouts, and straits. Choose nickel silver track instead of brass and thank me later.
Both will cause connectivity problems when oxidized, but the nickel silver will have a better conductivity over time. Experimentation is key to finding the model rail layout you so desire, so take your time.
When laying your track with combo track-roadbed products you can try various arrangements and not have to nail the track down in most cases.
Always get a reliable power pack for your model rails this will alleviate headaches. If you do however buy a prepacked train set, make sure to buy a quality power pack soon. Stay far away from low priced ready made toy store train sets. Those sets have poor quality written all over them, most of those sets come with brass track. They do have the advantage of carry accessories like buildings, trees, even the stations themselves, but you can find these in better quality on Ebay