You think it's better than getting a skimmer?
If the issue you are having is costs, and are only planning on one or the other, yes, I believe the sump is a better way to go. A canister, it's required flow, and a protein skimmer is gonna cost as much as, if not more than, a sump and skimmer.
All you are really looking at is a 10 gallon tank (I believe you said you had one..), maybe $20 worth of glass/silicone, and a pump (say $30-$50). Total: $70. A canister filter is going to be that amount alone. Plus skimmer. Either way, a well built skimmer should be around the higher range in price. Obviously high price doesn't equal quality, but it's close.
As I said, the choice is yours, but consider that a skimmer can go in a sump, and it is not required at start up. Filtration (mechanical and biological) is. Consider skimmers like waxing your car. It wont do a lot of good if you haven't washed the car first. Does that make any sense? That pretty well the best way I can describe it.
I'd say, sump, and later skimmer. If you go canister, then that will be the bulk of your investment, and wont allow funds for a skimmer either. Not to mention, it will be more money when/if you do "upgrade" to a sump. I'd hate to see you spend precious money on equipment repeatedly for the sake of convenience.