Hi. If your goal is to get up and running trains as fast as you can, track and then trains, in that order.
On the other hand, as you are on a tight budget, and if you can be patient, you will eventually have much more material and rolling items on hand when all is said and done if you buy things according to their price as their prices gain attractiveness....buy things when they go on sale.
For full enjoyment, a track plan needs some learned thinking. Read SpaceMouse's guide if you find one of his posts...it's a link under his signature. But for a general order of business, most folks identify their space, consider a robust track plan and supporting benchwork for the maximum fun, variety in operations, and longevity of the layout, and then acquire only the numbers of track sections and specialty items that they need...saves tons on unneeded purchase. You'll make more of those mistakes, and spend more, the less time you devote up-front to serious learning and thinking about how best to get a good plan for your space.
Next, you lay your trackage according to plan, wire it for power, and then you prove your track by running trains backwards and forward, engines under load and running free, to make sure it all works. Then you cover your tracks with wide painters tape, and then begin to add the scenery and structures as you had planned.
Note that some folks like to paint their surface before they lay tracks. This is somewhat more important when you have pink or blue extruded foam as your open layer. It doesn't look very realistic in those colours, so many folks paint it a light tan using latex paint that won't harm the foam.
How's that so far?
