It is generally assumed that a photographer needs a very expensive tripod. I will agree that a to get a very versatile, and very sturdy tripod that is also lightweight, especially one that is constructed from Carbon Fiber, that tripod is going to set you back a bundle. (BTW: Carbon fiber has advantages in addition to its relatively light weight).
However, if you can do without the versatility (for example using a tripod that will not articulate), and are willing and able to carry a bit more weight; it is possible to get a tripod on the used market for which you will not have to sell your first born child to afford...
In the days of film photography, many of the Navy Photographers depended on Leitz Tiltall tripods. I worked with these tripods and mounted 4x5 inch view cameras and press cameras upon them, I also used the Mamiya RB67 and the Pentax 6x7 which were not as large as the 4x5 inch cameras but were still a hefty weight. The Tiltall did a fine job. Granted, the 4x5 inch view cameras and the Mamiya RB-67 had revolving backs so you did not need to hang the camera cantilevered over on its side to shoot verticals. I have noticed some Leitz TiltAll tripods selling for around $125 - used. There are TiltAll (Type) tripods now distributed under the Star-D brand. I have no idea of their quality. I have only used the original Leitz models. BTW: I have never come across any Leitz branded gear that was not of very good quality!
Bogen-Manfrotto distributed a group of quite decent aluminum tripods which were sturdy, but not very light. There were the 30xx series and included the 3001, the 3011 and the 3021. Although, they did not articulate, if equipped with decent heads, they were quite sturdy camera mounts. Used Manfrotto 30xx leg sets are quite often available on eBay for a hundred U.S. Dollars or less. Sometimes you can find these pods with heads included for right around $100 or bit more.
Here is an example of a used Manfrotto 3021 tripod with a 3047 head.
http://www.ebay.com/itm/Bogen-by-Man...item2a503edf9e
This tripod is selling for $93.00 including shipping within the USA.
Before I purchased my full size Giottos Carbon Fiber MT-8180 with Arca Compatible Ball head I had used a Manfrotto 3001 Pro tripod for years. It was not as versatile as the Giottos but, it was still a very decent tripod and here's one selling for $124 USD with head and shipping.
http://www.ebay.com/itm/Manfrotto-30...item5d5864dde6
Are the above tripods equal to a top-line carbon fiber model? No, very likely not; especially in the versatility gained from the ability to articulate and the light weight. A good ball head is another advantage with better tripods - but ball heads can be used on Manfrotto leg sets also. However, will any of the above tripods support a digital camera with a reasonably long lens? Yes they will. Quite adequately.
Purchasing one of the above (type) tripods, used, and then wanting to upgrade after a couple of years would not be a big problem, because you could always resell that first tripod without taking a great financial beating.