Here’s my translation

Alan

Skikkja var annarr gripr, svá góð at slík fannst ei fyrir norðan Grikklands haf.
A cloak was a second treasure, so good (fine) that such-like was-found not north of (the) Grecian sea (ie Archipelago).

Tafl var inn þriði gripr ok var þat með rauðu gulli.
A tafl (‘Table’)-board was the third treasure and that was (made) with red gold.

Carbunculus var inn fjórði, svá stórr at hann vá níu aura.
A carbunculus (gemstone) was the fourth, so large that it weighed nine aurar (‘ounces’)

Sigrgarðr fór at finna Jónas ok kaupslagaði við hann ok falaði af honum skipit ok gripina, ok gaf honum í móti kastala þann sem faðir hans hafði honum gefit, ok jarlsnafn með, en hann fékk honum skipit í móti ok þessa góðgripi sem áðr eru nefndir ok þó skyldi hann eiga eptir jafnvægi skikkjunnar af rauðu gulli.
Sigrgarðr journeyed to find (meet) Jónas and bargained with him and demanded (to purchase) from him the-ship and the-treasures and gave him in-return that castle which his father had given him, and (the) name (ie title)-of-‘jarl’ (earl) with (it), but (and) he (Sigrgarðr) obtained for him (Jónas) the-ship in-return and these fine-treasures which already are (ie have been) named and besides (ok þó, þó, Z1) he should have in-addition (furthermore, beyond that, cf eptir, Z.iii.4) an-equal-weight of (ie to) (the) cloak of (ie in) red gold.

Hér með skiptu þeir litum, þvíat þat kunnu margir menn vel í þann tíma.
Here-with (ie at the same time, as part of the same deal) they changed (ie swapped) countenances (litr, CV, is the only reading that makes any sense here), because many people (men) knew that (presumably the fine art of countenance-swapping, neut) well at that time.

Síðan bjóst Sigrgarðr í kaupferðir ok ætluðu allir Jónas vera hvar sem hann fór.
After-that Sigrgarðr readied-himself (to go) into a trading-voyage and everyone thought (it) to be Jónas (ie because of the swapped countenances) wherever he journeyed.

Um síðir kom hann austr í Tartaría, ok ei allnær því sem meykonungrinn sat.
At last he came east into Tartaría, and not (ei = ekki) very-near to that (place) where the-maiden-king sat (ie resided)

Hann lét falan varning sinn ok sýndi gripina, ok mat svá dýrt at engi reiðaðist við at kaupa.
He placed for-sale (falr, masc acc sg) his merchandise and showed the-treasures, and charged (past tense of meta, verb) so expensively (ie much) that no-one was-decided (‘was-weighed in the balance’, passive weak form of reiða, Z6?) to make a bargain (do a deal, kaupa við)

Þetta var sagt meykonunginum, ok lofuðu menn mjög gripina fyrir henni.
This was said to the-maiden-king, and people (men) praised greatly the-treasures before/for her (ie in her presence?, for her benefit?)

Hon gjörir nú heimanferð sína til móts við Jónas, en þá er hon kemur í þá höfn er hann lá fyrir, kallar hon hann til tals við sik ok spurði hvárt hann hefði gripi svá góða sem sagt væri.
She makes now her journey-from-home to a meeting with Jónas (in reality Sigrgarðr), but (and) when she comes into that harbour where he lay (was situated) before (ie  ashore of), she calls (summons) him to a conversation with herself and asked whether he had treasures as good as was said.

Hann segir at lítils væri vert um þá, en hon kveðst vilja sjá ok kaupa ef falir væri.
He says that (it) was worthy of little concerning them (ie they were of no great value), but (and) she declares-of-herself to want to see (them) and to buy if (they) were for-sale (falr)

Hann kvað ei fala vera.
He declared (of them) not to be for sale.

Hon spurði hvárt hann ætlaði sína gæfu meiri enn annarra, ef hann vildi synja henni kaups.
She asked whether he thought his good-luck greater than of others, if he wanted to refuse a deal with her.

Hann kveðst hafa ætlað gripina Miklagarðs konungi.
He declared-of-himself to have intended the-treasures for (the) king of Miklagarðr (Constantinople)

Hon kveðst ei vita þann konung at hon vildi gripi fyrir missa.
She declared-of-herself not to know that (read: any) king that she wanted be-without (the) costly-things for (ie that king whom she would rather have the treasures ahead/in lieu of herself)

Hon bað hann meta svá dýrt sem hann vildi.
She bade him to charge as expensively (ie as much) as he wanted.

Hann kvað hana mundu sjá vilja áðr, en sagðist ei sýna vilja nema hon lofaði at taka ei með ofríki af honum, en hon segir at hann þyrfti ei at minna sik á þat.
He declared (that) she would want to see (them) before-hand, but (and) said-of-himself not to want to show (them) unless she promised (lofa, Z3) to not take (them) from him with (ie by means of) sheer-force (ofríki, CV) , but (and) she says that he needed not to bother himself (lit: remind himself) about that.

Kveðst hafa nóga makt at taka bæði hann ok svá allt þat sem hann á ok færi með. 
(She) declared-of-herself to have enough power to seize both him and also all that which he possessed and (to have)(the) opportunity (the ability to do so, foeri, Z1, Z2) with it (ie as well).