I agree with dingy that there are certainly better options out there (many at that), especially for EDC purposes as fixed blades are many times not realistic in that scope. The opinel is a great suggestion though.
As far as your two options, IMO the Marttini is a better knife all around, but for EDC purposes it is probably not realistic. The hard plastic sheath would greatly hinder the purpose of EDC. The schrade sharpfinger is smaller and comes with a leather sheath I believe which would make it a better carry knife than the Marttini.
If you're dead set on a budget fixed blade you may want to consider smaller style knives as they would carry better and be more realistic and applicable to true EDC purposes.
A couple that come to mind are the CRKT Folts Minimalist Bowie and CRKT S.P.E.W., these are neck knives but have built in belt clips which would aid in carry for the EDC function. The SPEW has a decent sized blade but remains a smaller knife which would be a good fixed EDC option. Both are between $20-30
Sticking along the lines of the Marttini, a good Mora and also a Cold Steel Pendleton can both be had for about $14
Another good option for fixed blade EDC would be a Timberline lightfoot mini pit bull, great clip and good blade, about $20-30
Like stated, as far as an EDC, a folder would be much better suited. But if you are set on a fixed blade it would be wise to focus on the carry aspect of the knife more than the actual knife as the EDC portion will be much more of a chore than actually using the fixed blade.
Let me know if you need anything else,
Russ