diff --git a/contracts/IAdapter.json b/contracts/IAdapter.json
index 12cda06..5109f14 100644
--- a/contracts/IAdapter.json
+++ b/contracts/IAdapter.json
@@ -1,7 +1,7 @@
 {
   "_format": "hh-sol-artifact-1",
   "contractName": "IAdapter",
-  "sourceName": "contracts/IAdapter.sol",
+  "sourceName": "contracts/interfaces/IAdapter.sol",
   "abi": [
     {
       "inputs": [],
@@ -23,6 +23,11 @@
           "name": "recipient",
           "type": "address"
         },
+        {
+          "internalType": "uint256",
+          "name": "price",
+          "type": "uint256"
+        },
         {
           "internalType": "uint8",
           "name": "v",
diff --git a/contracts/ISubscription.json b/contracts/ISubscription.json
index b1ee744..ae55cce 100644
--- a/contracts/ISubscription.json
+++ b/contracts/ISubscription.json
@@ -1,7 +1,7 @@
 {
   "_format": "hh-sol-artifact-1",
   "contractName": "ISubscription",
-  "sourceName": "contracts/ISubscription.sol",
+  "sourceName": "contracts/interfaces/ISubscription.sol",
   "abi": [
     {
       "anonymous": false,
diff --git a/docs/openapi.yaml b/docs/openapi.yaml
index f0ed1a5..7d56301 100644
--- a/docs/openapi.yaml
+++ b/docs/openapi.yaml
@@ -141,6 +141,13 @@ paths:
   /api/v1/accounts/authorize_subscription:
     get:
       summary: Get authorization for setting up paid subscription.
+      parameters:
+        - name: price
+          in: query
+          description: Subscription price
+          required: true
+          schema:
+            type: number
       responses:
         200:
           description: Signature created
diff --git a/src/ethereum/signatures.rs b/src/ethereum/signatures.rs
index 5049eb6..ecf56ad 100644
--- a/src/ethereum/signatures.rs
+++ b/src/ethereum/signatures.rs
@@ -3,7 +3,7 @@ use std::str::FromStr;
 
 use secp256k1::{Error as KeyError, SecretKey, rand::rngs::OsRng};
 use serde::Serialize;
-use web3::ethabi::{token::Token, encode};
+use web3::ethabi::{token::Token, encode as encode_tokens};
 use web3::signing::{
     keccak256,
     recover,
@@ -12,7 +12,7 @@ use web3::signing::{
     SecretKeyRef,
     SigningError,
 };
-use web3::types::{Address, H256, Recovery, U256};
+use web3::types::{Address, H256, Recovery};
 
 /// Generates signing key
 pub fn generate_ecdsa_key() -> SecretKey {
@@ -129,6 +129,11 @@ pub fn recover_address(
 
 pub type CallArgs = Vec<Box<dyn AsRef<[u8]>>>;
 
+pub fn encode_uint256(value: u64) -> Vec<u8> {
+    let token = Token::Uint(value.into());
+    encode_tokens(&[token])
+}
+
 pub fn sign_contract_call(
     signing_key: &str,
     chain_id: u32,
@@ -136,9 +141,7 @@ pub fn sign_contract_call(
     method_name: &str,
     method_args: CallArgs,
 ) -> Result<SignatureData, SignatureError> {
-    let chain_id: U256 = chain_id.into();
-    let chain_id_token = Token::Uint(chain_id);
-    let chain_id_bin = encode(&[chain_id_token]);
+    let chain_id_bin = encode_uint256(chain_id.into());
     let contract_address = Address::from_str(contract_address)
         .map_err(|_| SignatureError::InvalidData)?;
     let mut message = [
diff --git a/src/ethereum/subscriptions.rs b/src/ethereum/subscriptions.rs
index eee7876..ec546ca 100644
--- a/src/ethereum/subscriptions.rs
+++ b/src/ethereum/subscriptions.rs
@@ -25,7 +25,12 @@ use crate::models::subscriptions::queries::{
 };
 use crate::models::users::queries::get_user_by_wallet_address;
 use super::errors::EthereumError;
-use super::signatures::{sign_contract_call, CallArgs, SignatureData};
+use super::signatures::{
+    encode_uint256,
+    sign_contract_call,
+    CallArgs,
+    SignatureData,
+};
 use super::sync::{save_current_block_number, SyncState};
 use super::utils::{address_to_string, parse_address};
 
@@ -197,9 +202,13 @@ pub async fn check_subscriptions(
 pub fn create_subscription_signature(
     blockchain_config: &BlockchainConfig,
     user_address: &str,
+    price: u64,
 ) -> Result<SignatureData, EthereumError> {
     let user_address = parse_address(user_address)?;
-    let call_args: CallArgs = vec![Box::new(user_address)];
+    let call_args: CallArgs = vec![
+        Box::new(user_address),
+        Box::new(encode_uint256(price)),
+    ];
     let signature = sign_contract_call(
         &blockchain_config.signing_key,
         blockchain_config.ethereum_chain_id(),
diff --git a/src/mastodon_api/accounts/types.rs b/src/mastodon_api/accounts/types.rs
index afafec9..e18d593 100644
--- a/src/mastodon_api/accounts/types.rs
+++ b/src/mastodon_api/accounts/types.rs
@@ -228,6 +228,11 @@ pub struct IdentityProofData {
     pub signature: String,
 }
 
+#[derive(Deserialize)]
+pub struct SubscriptionQueryParams {
+    pub price: u64,
+}
+
 // TODO: actix currently doesn't support parameter arrays
 // https://github.com/actix/actix-web/issues/2044
 #[derive(Deserialize)]
diff --git a/src/mastodon_api/accounts/views.rs b/src/mastodon_api/accounts/views.rs
index e513d54..2dd46d4 100644
--- a/src/mastodon_api/accounts/views.rs
+++ b/src/mastodon_api/accounts/views.rs
@@ -63,6 +63,7 @@ use super::types::{
     IdentityProofData,
     RelationshipQueryParams,
     StatusListQueryParams,
+    SubscriptionQueryParams,
 };
 
 #[post("")]
@@ -285,6 +286,7 @@ async fn authorize_subscription(
     auth: BearerAuth,
     config: web::Data<Config>,
     db_pool: web::Data<Pool>,
+    query_params: web::Query<SubscriptionQueryParams>,
 ) -> Result<HttpResponse, HttpError> {
     let db_client = &**get_database_client(&db_pool).await?;
     let current_user = get_current_user(db_client, auth.token()).await?;
@@ -297,6 +299,7 @@ async fn authorize_subscription(
     let signature = create_subscription_signature(
         blockchain_config,
         &wallet_address,
+        query_params.price,
     ).map_err(|_| HttpError::InternalError)?;
     Ok(HttpResponse::Ok().json(signature))
 }