तेन क्रीतम्

The thirteen affixes taught in 5.1.18-36 have the sense of 'purchased with this price' and are added to a word in the third case in construction.
The thirteen affixes ठञ्, ठक्, ठन्, यत्, कन्, ड्वुन्, टिठन्, अञ्, अण्, ख, ईकन्, यत् and अण् have already been taught. Now is taught their sense, and the case in construction of the word to which they should be added. The तेन shows that the word must be in the 3rd case in construction : and क्रीतम् shows that the sense is that of 'purchased'. The illustrations have already been given in the previous sutras. Some more may be mentioned here. Thus सप्तत्याक्रीतं = साप्ततिकम्, आशीतिकम्, नैष्किकम्, पाणिकम्, पादिकम्, माषिकम्, शत्यम्, शतिकम्, द्विकम्, त्रिकम् &c.

The affix will come after a word in the 3rd case in construction when it means 'price,' and the force of the 3rd case is that of 'instrument' 2.3.18 and not that of 'agent.' Therefore, there is no affixing in the words देवदत्तेन क्रीतं or पाणिना क्रीतं ॥

Nor does the affix come after a dual or a plural. Thus प्रस्थाभ्यां क्रीतं or प्रस्थैः क्रीतं, there is no affixing, as it is not the idiom. But द्वाभ्यां क्रीतं = द्विकम्, त्रिकम्, पंचकम्, मुद्गैः क्रीतं = मौद्गिकम्, माषिकम्. Here there is affixing after a dual and plural, for the words द्वि, त्रि are essentially dual or plural, and in the case of मुद्गः and माषः, those are always used in the plural, for it is not possible to purchase anything with a single grain of मुद्ग or माषः ॥