"Given the 1968-era graphics and the condition you described, a realistic Northern California value is about $25 to $45. If you price it for a local sale, $30–$35 is a sensible asking range, while $20–$25 is closer to a quick-sale price.
Why this range
A similar 1968 Matchbox collector case in good condition but missing trays and a handle was listed at $40 locally, which is a useful benchmark for your case even though your handle is intact. Another recent listing shows vintage Lesney/Matchbox cases commonly trading around the mid-20s to low-30s depending on completeness and condition.
Condition impact
Your case keeps value because the exterior color is still strong and the closure works. The missing tray and slight mildew staining reduce it, but not enough to make it only a parts item; it still reads as a displayable collector piece.
Model-specific note
The Mercedes coupe and dump truck graphics help identify it as a later 1960s Matchbox carrying case, which is generally more collectible than an unbranded toy box."
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