Getting started in large scale railways is no more complicated than smaller - indoor - scales. Plus for the money starter sets continue to be the most cost effective way of getting a loco, track and controller.
Most new modellers have historically started with an LGB set - they have all the basics, come from a firm offering a large range of extra products and often have extra features such as sound, lights or smoke effects. Recently we've seen an increase in popularity of American starter sets from Aristocraft - excellent value items which come with long guarantees. Bachmann sets are cheap and in some cases should be considered Toys rather than models - great for kids.
Lastly at the top end of the market is Marklin - a true Gauge 1 model railway system - frequently used indoors (in part due to it's cost!), provided you have a room large enough of course.