There is nothing wrong with accepting a gift and giving something of similar value to the giver

Al-Bukhaari (2585) narrated that ‘Aa’ishah said: The
Messenger of Allaah (peace and blessings of Allaah be upon him) used to
accept gifts and reward people for giving them. 

“Reward people for giving them” means giving the giver
something of equal value at least in return. This was the view of al-Haafiz
in al-Fath. 

This hadeeth indicates
that accepting gifts and giving something of equal value to the giver is the
way of the Prophet (peace and blessings of Allaah be upon him). 

The Prophet (peace and blessings of Allaah be upon him)
enjoined responding in kind to favours, as he said: “Whoever does you a
favour, respond in kind, and if you cannot find the means of doing so, then
keep praying for him until you think that you have responded in kind.”
Narrated by Abu Dawood, 1672. classed as saheeh by al-Albaani in Saheeh
Abi Dawood. 

“Whoever does you a favour” means, whoever treats you kindly
in word or deed. 

“Respond in kind” means, treat him kindly just as he has
treated you kindly. 

“If you cannot find the means of doing so” means if you do
not have the money. 

“Until you think that you have responded in kind” means,
repeat the du’aa’ until you think that you have given him his due. 

One of the du’aa’s that you can say is Jazaak Allaahu
khayran (may Allaah reward you with good). Al-Tirmidhi (2035) narrated
that Usaamah ibn Zayd said: The Messenger of Allaah (peace and
blessings of Allaah be upon him) said: “Whoever has a favour done for him
and says Jazaak Allaahu khayran (may Allaah reward you with good) has
done his utmost to thank him.” Narrated by al-Tirmidhi, 2035; classed as
saheeh by al-Albaani in Saheeh al-Tirmidhi. 

“Done his utmost to thank
him” means, he has done his utmost to express his thanks, because he has
acknowledged his shortcomings and that he is unable to reward him and thank
him, so he refers the matter to Allaah, that He might reward him in the best
manner. One of them said: If you are unable to give him back in kind, then
speak at length thanking him and making du’aa’ for him. From Tuhfat
al-Ahwadhi. 

The Standing Committee was asked a similar question, and
replied as follows: 

There is nothing wrong
with accepting it (an amount of money as a gift), without you longing for
that, and you can respond in kind if you are able to with an appropriate
gift, or you can make du’aa’ for him, because the Prophet (peace and
blessings of Allaah be upon him) said: “Whoever does you a favour, respond
in kind, and if you cannot find the means of doing so, then keep praying for
him until you think that you have responded in kind.”   Narrated by Abu
Dawood and al-Nasaa’i. 

Fataawa al-Lajnah al-Daa’imah,
16/171 

And Allaah knows best.